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Add comprehensive C learning materials with specialized topic tutorials
Complete learning guide covering ALL C concepts from beginner to advanced: Main Guide (LEARNING_C_WITH_CLAY.md): - Added Chapters 3-5: Operators, Control Flow, Loops - Enhanced Chapters 6-13: Functions, Pointers, Structs, Arrays, Strings, Type Casting, Storage Classes, Recursion - All chapters include extensive Clay library examples - Progressive difficulty from basics to advanced topics Specialized Tutorial Files (docs/): - 14_bit_manipulation.md: Comprehensive bit operations guide * Bitwise operators, masks, flags * Counting bits, power of 2 operations * Practical applications with Clay examples - 21_standard_library.md: C Standard Library overview * stdio.h, stdlib.h, string.h, math.h * Clay's zero-dependency approach * Custom implementations vs stdlib - 22_file_io.md: Complete File I/O guide * Text and binary file operations * Configuration files for Clay apps * Error handling and best practices - 23_command_line_arguments.md: CLI argument parsing * argc/argv basics * Flag parsing and subcommands * Clay application configuration examples - README_C_TUTORIALS.md: Master index and learning guide * Complete chapter overview * Learning path recommendations * Progress tracking checklist * Prerequisites and setup instructions Features: - 24 comprehensive chapters covering all C concepts - 100+ code examples with detailed explanations - Real-world patterns from Clay library throughout - Practice exercises for each chapter - Modular organization for easy navigation - Zero-dependency programming concepts - Professional C development practices Total content: ~70,000+ words of detailed tutorials
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Claude
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1. [Introduction to C and Clay](#introduction)
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2. [Chapter 1: C Basics - Your First Program](#chapter-1)
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3. [Chapter 2: Variables and Data Types](#chapter-2)
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4. [Chapter 3: Functions](#chapter-3)
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5. [Chapter 4: Pointers - The Heart of C](#chapter-4)
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6. [Chapter 5: Structs and Typedef](#chapter-5)
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7. [Chapter 6: Arrays and Memory](#chapter-6)
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8. [Chapter 7: Preprocessor and Macros](#chapter-7)
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9. [Chapter 8: Advanced Macros and Metaprogramming](#chapter-8)
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10. [Chapter 9: Memory Management](#chapter-9)
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11. [Chapter 10: Header Files and Project Organization](#chapter-10)
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12. [Chapter 11: Enums and Unions](#chapter-11)
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13. [Chapter 12: Function Pointers and Callbacks](#chapter-12)
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14. [Chapter 13: Building Complete Programs](#chapter-13)
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4. [Chapter 3: Operators](#chapter-3)
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5. [Chapter 4: Control Flow](#chapter-4)
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6. [Chapter 5: Loops](#chapter-5)
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7. [Chapter 6: Functions](#chapter-6)
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8. [Chapter 7: Pointers - The Heart of C](#chapter-7)
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9. [Chapter 8: Structs and Typedef](#chapter-8)
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10. [Chapter 9: Arrays and Memory](#chapter-9)
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11. [Chapter 10: Strings](#chapter-10)
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12. [Chapter 11: Type Casting and Qualifiers](#chapter-11)
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13. [Chapter 12: Storage Classes and Scope](#chapter-12)
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14. [Chapter 13: Recursion](#chapter-13)
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15. [Chapter 14: Bit Manipulation](#chapter-14)
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16. [Chapter 15: Preprocessor and Macros](#chapter-15)
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17. [Chapter 16: Advanced Macros and Metaprogramming](#chapter-16)
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18. [Chapter 17: Memory Management](#chapter-17)
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19. [Chapter 18: Header Files and Project Organization](#chapter-18)
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20. [Chapter 19: Enums and Unions](#chapter-19)
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21. [Chapter 20: Function Pointers and Callbacks](#chapter-20)
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22. [Chapter 21: Standard Library Basics](#chapter-21)
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23. [Chapter 22: File I/O](#chapter-22)
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24. [Chapter 23: Command-Line Arguments](#chapter-23)
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25. [Chapter 24: Building Complete Programs](#chapter-24)
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---
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@ -219,7 +230,809 @@ const Clay_Color CLAY_COLOR_BLACK = {0, 0, 0, 255};
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---
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## Chapter 3: Functions {#chapter-3}
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## Chapter 3: Operators {#chapter-3}
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### 3.1 Arithmetic Operators
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Basic math operations:
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```c
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int main(void) {
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int a = 10, b = 3;
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int sum = a + b; // 13 (addition)
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int diff = a - b; // 7 (subtraction)
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int product = a * b; // 30 (multiplication)
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int quotient = a / b; // 3 (integer division)
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int remainder = a % b; // 1 (modulo/remainder)
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// Floating-point division
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float result = 10.0f / 3.0f; // 3.333...
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return 0;
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}
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```
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### 3.2 Increment and Decrement
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```c
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int main(void) {
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int x = 5;
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// Post-increment (use then increment)
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int a = x++; // a = 5, x = 6
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// Pre-increment (increment then use)
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int b = ++x; // x = 7, b = 7
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// Post-decrement
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int c = x--; // c = 7, x = 6
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// Pre-decrement
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int d = --x; // x = 5, d = 5
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return 0;
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}
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```
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**Clay Example** (from clay.h):
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```c
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// Pre-increment used for index management
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Clay__currentContext->layoutElements.length++;
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// Post-increment to get current then move
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element = array->internalArray[index++];
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```
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### 3.3 Relational Operators
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Compare values:
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```c
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int main(void) {
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int a = 10, b = 20;
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int equal = (a == b); // 0 (false)
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int notEqual = (a != b); // 1 (true)
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int less = (a < b); // 1 (true)
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int lessOrEqual = (a <= b); // 1 (true)
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int greater = (a > b); // 0 (false)
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int greaterOrEqual = (a >= b); // 0 (false)
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return 0;
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}
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```
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**Clay Example** (from clay.h):
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```c
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static inline float Clay__Max(float a, float b) {
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return a > b ? a : b; // Using > operator
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}
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if (config->type == CLAY_SIZING_TYPE_FIXED) {
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// Using == operator
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}
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```
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### 3.4 Logical Operators
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Boolean logic:
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```c
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int main(void) {
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int a = 1, b = 0; // 1 = true, 0 = false
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int andResult = a && b; // 0 (both must be true)
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int orResult = a || b; // 1 (at least one true)
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int notResult = !a; // 0 (logical NOT)
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// Short-circuit evaluation
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if (ptr != NULL && *ptr > 0) {
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// Safe: *ptr only evaluated if ptr != NULL
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}
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return 0;
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}
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```
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**Clay Example** (from clay.h):
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```c
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if (element->layoutConfig &&
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element->layoutConfig->sizing.width.type == CLAY_SIZING_TYPE_GROW) {
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// Short-circuit: second condition only checked if first is true
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}
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```
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### 3.5 Bitwise Operators
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Work on individual bits:
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```c
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int main(void) {
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unsigned int a = 5; // 0101 in binary
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unsigned int b = 3; // 0011 in binary
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unsigned int and = a & b; // 0001 = 1 (AND)
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unsigned int or = a | b; // 0111 = 7 (OR)
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unsigned int xor = a ^ b; // 0110 = 6 (XOR)
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unsigned int not = ~a; // 1010 (NOT, inverts all bits)
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// Bit shifts
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unsigned int leftShift = a << 1; // 1010 = 10 (multiply by 2)
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unsigned int rightShift = a >> 1; // 0010 = 2 (divide by 2)
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return 0;
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}
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```
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**Clay Example** (from clay.h):
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```c
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// Bit flags for corner radius
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typedef enum {
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CLAY_CORNER_RADIUS_TOP_LEFT = 1 << 0, // 0001
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CLAY_CORNER_RADIUS_TOP_RIGHT = 1 << 1, // 0010
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CLAY_CORNER_RADIUS_BOTTOM_LEFT = 1 << 2, // 0100
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CLAY_CORNER_RADIUS_BOTTOM_RIGHT = 1 << 3 // 1000
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} Clay_CornerRadiusSet;
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// Combine flags with OR
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int flags = CLAY_CORNER_RADIUS_TOP_LEFT | CLAY_CORNER_RADIUS_TOP_RIGHT;
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// Check if flag is set with AND
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if (flags & CLAY_CORNER_RADIUS_TOP_LEFT) {
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// Top left corner has radius
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}
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```
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### 3.6 Assignment Operators
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```c
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int main(void) {
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int x = 10;
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x += 5; // x = x + 5 (15)
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x -= 3; // x = x - 3 (12)
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x *= 2; // x = x * 2 (24)
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x /= 4; // x = x / 4 (6)
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x %= 4; // x = x % 4 (2)
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// Bitwise compound assignments
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x &= 3; // x = x & 3
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x |= 4; // x = x | 4
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x ^= 1; // x = x ^ 1
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x <<= 1; // x = x << 1
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x >>= 1; // x = x >> 1
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return 0;
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}
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```
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### 3.7 Ternary Operator
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Compact if-else:
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```c
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int main(void) {
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int a = 10, b = 20;
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// condition ? value_if_true : value_if_false
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int max = (a > b) ? a : b;
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// Equivalent to:
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int max2;
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if (a > b) {
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max2 = a;
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} else {
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max2 = b;
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}
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return 0;
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}
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```
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**Clay Example** (from clay.h):
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```c
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static inline float Clay__Min(float a, float b) {
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return a < b ? a : b; // Ternary operator
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}
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// Nested ternary (less readable)
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int result = (x > 0) ? 1 : (x < 0) ? -1 : 0;
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```
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### 3.8 sizeof Operator
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Get size of type or variable:
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```c
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#include <stdio.h>
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int main(void) {
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printf("int: %zu bytes\n", sizeof(int));
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printf("float: %zu bytes\n", sizeof(float));
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printf("double: %zu bytes\n", sizeof(double));
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printf("char: %zu bytes\n", sizeof(char));
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printf("pointer: %zu bytes\n", sizeof(void*));
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int arr[10];
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printf("array: %zu bytes\n", sizeof(arr)); // 40 bytes (10 * 4)
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return 0;
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}
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```
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**Clay Example** (from clay.h):
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```c
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// Get size of struct
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size_t size = sizeof(Clay_LayoutElement);
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// Allocate memory
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void *mem = malloc(count * sizeof(Clay_RenderCommand));
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// Calculate array length
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int length = sizeof(array) / sizeof(array[0]);
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```
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### 3.9 Comma Operator
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Evaluate multiple expressions:
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```c
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int main(void) {
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int a, b, c;
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// Comma operator: evaluates left to right, returns rightmost
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a = (b = 5, c = 10, b + c); // a = 15
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// Common in for loops
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for (int i = 0, j = 10; i < j; i++, j--) {
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// i increments, j decrements
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}
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return 0;
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}
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```
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**Clay Example** (from clay.h):
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```c
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// Used in macro for-loop trick
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#define CLAY(...) \
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for ( \
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CLAY__ELEMENT_DEFINITION_LATCH = ( \
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Clay__OpenElement(), /* First */ \
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Clay__ConfigureOpenElement(...), /* Second */ \
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0 /* Result */ \
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); \
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/* ... */ \
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)
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```
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### 3.10 Operator Precedence
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Order of evaluation (high to low):
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```c
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int main(void) {
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// Precedence matters!
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int x = 2 + 3 * 4; // 14, not 20 (* before +)
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int y = (2 + 3) * 4; // 20 (parentheses first)
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// Common precedence
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// 1. () [] -> .
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// 2. ! ~ ++ -- + - * & sizeof
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// 3. * / %
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// 4. + -
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// 5. << >>
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// 6. < <= > >=
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// 7. == !=
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// 8. &
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// 9. ^
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// 10. |
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// 11. &&
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// 12. ||
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// 13. ?:
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// 14. = += -= etc.
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// 15. ,
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return 0;
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}
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```
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**Tip**: When in doubt, use parentheses for clarity!
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### 3.11 Key Concepts Learned
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- ✅ Arithmetic operators (+, -, *, /, %)
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- ✅ Increment/decrement (++, --)
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- ✅ Relational operators (==, !=, <, >, <=, >=)
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- ✅ Logical operators (&&, ||, !)
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- ✅ Bitwise operators (&, |, ^, ~, <<, >>)
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- ✅ Assignment operators (=, +=, -=, etc.)
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- ✅ Ternary operator (?:)
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- ✅ sizeof operator
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- ✅ Operator precedence
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---
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## Chapter 4: Control Flow {#chapter-4}
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### 4.1 if Statement
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Basic conditional execution:
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```c
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int main(void) {
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int age = 18;
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if (age >= 18) {
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printf("Adult\n");
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}
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return 0;
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}
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```
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**Clay Example** (from clay.h):
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```c
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if (layoutElement->layoutConfig) {
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// Process layout config
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}
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if (element == NULL) {
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return; // Early return
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}
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```
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### 4.2 if-else Statement
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```c
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int main(void) {
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int score = 75;
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if (score >= 60) {
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printf("Pass\n");
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} else {
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printf("Fail\n");
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}
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return 0;
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}
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```
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### 4.3 else-if Chains
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```c
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int main(void) {
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int grade = 85;
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if (grade >= 90) {
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printf("A\n");
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} else if (grade >= 80) {
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printf("B\n");
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} else if (grade >= 70) {
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printf("C\n");
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} else if (grade >= 60) {
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printf("D\n");
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} else {
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printf("F\n");
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}
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return 0;
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}
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```
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**Clay Example** (from clay.h):
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```c
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if (config->type == CLAY_SIZING_TYPE_FIT) {
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// Handle FIT sizing
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} else if (config->type == CLAY_SIZING_TYPE_GROW) {
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// Handle GROW sizing
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} else if (config->type == CLAY_SIZING_TYPE_FIXED) {
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// Handle FIXED sizing
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}
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```
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### 4.4 Nested if Statements
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```c
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int main(void) {
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int age = 25;
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int hasLicense = 1;
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if (age >= 18) {
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if (hasLicense) {
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printf("Can drive\n");
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} else {
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printf("Need license\n");
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}
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} else {
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printf("Too young\n");
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}
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return 0;
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}
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```
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### 4.5 switch Statement
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Multiple conditions based on value:
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```c
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int main(void) {
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int day = 3;
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switch (day) {
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case 1:
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printf("Monday\n");
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break;
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case 2:
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printf("Tuesday\n");
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break;
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case 3:
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printf("Wednesday\n");
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break;
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case 4:
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printf("Thursday\n");
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break;
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case 5:
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printf("Friday\n");
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break;
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case 6:
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case 7:
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printf("Weekend\n");
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break;
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default:
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printf("Invalid day\n");
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break;
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}
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return 0;
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}
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```
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**Important**: `break` is required to exit switch, otherwise execution "falls through"!
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**Clay Example** (from clay.h):
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```c
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switch (commandType) {
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case CLAY_RENDER_COMMAND_TYPE_RECTANGLE: {
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// Render rectangle
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break;
|
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}
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case CLAY_RENDER_COMMAND_TYPE_TEXT: {
|
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// Render text
|
||||
break;
|
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}
|
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case CLAY_RENDER_COMMAND_TYPE_IMAGE: {
|
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// Render image
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break;
|
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}
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default: {
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// Unknown command
|
||||
break;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### 4.6 Fall-through in switch
|
||||
|
||||
Intentional fall-through can be useful:
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
char ch = 'a';
|
||||
|
||||
switch (ch) {
|
||||
case 'a':
|
||||
case 'e':
|
||||
case 'i':
|
||||
case 'o':
|
||||
case 'u':
|
||||
printf("Vowel\n");
|
||||
break;
|
||||
default:
|
||||
printf("Consonant\n");
|
||||
break;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### 4.7 goto Statement
|
||||
|
||||
Jump to a label (use sparingly):
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
int error = processData();
|
||||
|
||||
if (error) {
|
||||
goto cleanup;
|
||||
}
|
||||
|
||||
error = processMoreData();
|
||||
|
||||
if (error) {
|
||||
goto cleanup;
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
||||
cleanup:
|
||||
freeResources();
|
||||
return 1;
|
||||
}
|
||||
```
|
||||
|
||||
**When goto is acceptable:**
|
||||
- Error handling with cleanup
|
||||
- Breaking out of nested loops
|
||||
- State machines
|
||||
|
||||
**Clay doesn't use goto** - demonstrates clean error handling without it!
|
||||
|
||||
### 4.8 Key Concepts Learned
|
||||
- ✅ if, else, else-if statements
|
||||
- ✅ Nested conditionals
|
||||
- ✅ switch-case statements
|
||||
- ✅ break in switch
|
||||
- ✅ Fall-through behavior
|
||||
- ✅ goto statement (use carefully)
|
||||
|
||||
---
|
||||
|
||||
## Chapter 5: Loops {#chapter-5}
|
||||
|
||||
### 5.1 while Loop
|
||||
|
||||
Repeat while condition is true:
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
int count = 0;
|
||||
|
||||
while (count < 5) {
|
||||
printf("%d\n", count);
|
||||
count++;
|
||||
}
|
||||
// Output: 0 1 2 3 4
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay Example** (from clay.h):
|
||||
```c
|
||||
while (currentElement != NULL) {
|
||||
// Process element
|
||||
currentElement = currentElement->next;
|
||||
}
|
||||
```
|
||||
|
||||
### 5.2 do-while Loop
|
||||
|
||||
Execute at least once, then check condition:
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
int count = 0;
|
||||
|
||||
do {
|
||||
printf("%d\n", count);
|
||||
count++;
|
||||
} while (count < 5);
|
||||
// Output: 0 1 2 3 4
|
||||
|
||||
// Even runs once if condition is false
|
||||
int x = 10;
|
||||
do {
|
||||
printf("Runs once\n");
|
||||
} while (x < 5); // False, but body already executed
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### 5.3 for Loop
|
||||
|
||||
Most common loop for counting:
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
// for (initialization; condition; increment)
|
||||
for (int i = 0; i < 5; i++) {
|
||||
printf("%d\n", i);
|
||||
}
|
||||
// Output: 0 1 2 3 4
|
||||
|
||||
// Multiple variables
|
||||
for (int i = 0, j = 10; i < j; i++, j--) {
|
||||
printf("i=%d, j=%d\n", i, j);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay Example** (from clay.h):
|
||||
```c
|
||||
for (int i = 0; i < elementCount; i++) {
|
||||
Clay_LayoutElement *element = &elements[i];
|
||||
// Process element
|
||||
}
|
||||
|
||||
// Iterate backwards
|
||||
for (int i = array->length - 1; i >= 0; i--) {
|
||||
// Process in reverse
|
||||
}
|
||||
```
|
||||
|
||||
### 5.4 break Statement
|
||||
|
||||
Exit loop early:
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
for (int i = 0; i < 10; i++) {
|
||||
if (i == 5) {
|
||||
break; // Exit loop when i is 5
|
||||
}
|
||||
printf("%d\n", i);
|
||||
}
|
||||
// Output: 0 1 2 3 4
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay Example** (from clay.h):
|
||||
```c
|
||||
for (int i = 0; i < maxIterations; i++) {
|
||||
if (found) {
|
||||
break; // Stop searching
|
||||
}
|
||||
// Continue searching...
|
||||
}
|
||||
```
|
||||
|
||||
### 5.5 continue Statement
|
||||
|
||||
Skip to next iteration:
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
for (int i = 0; i < 10; i++) {
|
||||
if (i % 2 == 0) {
|
||||
continue; // Skip even numbers
|
||||
}
|
||||
printf("%d\n", i);
|
||||
}
|
||||
// Output: 1 3 5 7 9 (odd numbers only)
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### 5.6 Nested Loops
|
||||
|
||||
Loops inside loops:
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
// Print multiplication table
|
||||
for (int i = 1; i <= 5; i++) {
|
||||
for (int j = 1; j <= 5; j++) {
|
||||
printf("%3d ", i * j);
|
||||
}
|
||||
printf("\n");
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay Example** (from clay.h):
|
||||
```c
|
||||
// Iterate through 2D structure
|
||||
for (int row = 0; row < rows; row++) {
|
||||
for (int col = 0; col < cols; col++) {
|
||||
Clay_LayoutElement *cell = GetCell(row, col);
|
||||
// Process cell
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### 5.7 Breaking from Nested Loops
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
int found = 0;
|
||||
|
||||
for (int i = 0; i < 10 && !found; i++) {
|
||||
for (int j = 0; j < 10; j++) {
|
||||
if (i * j == 42) {
|
||||
found = 1;
|
||||
break; // Only breaks inner loop
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Alternative with goto (acceptable here)
|
||||
for (int i = 0; i < 10; i++) {
|
||||
for (int j = 0; j < 10; j++) {
|
||||
if (i * j == 42) {
|
||||
goto found_it; // Breaks both loops
|
||||
}
|
||||
}
|
||||
}
|
||||
found_it:
|
||||
printf("Found it!\n");
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### 5.8 Infinite Loops
|
||||
|
||||
```c
|
||||
int main(void) {
|
||||
// Infinite loop - use break to exit
|
||||
while (1) { // or for(;;) or while(true)
|
||||
int input = getInput();
|
||||
if (input == -1) {
|
||||
break;
|
||||
}
|
||||
processInput(input);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### 5.9 Loop Patterns
|
||||
|
||||
**Count up:**
|
||||
```c
|
||||
for (int i = 0; i < n; i++) { }
|
||||
```
|
||||
|
||||
**Count down:**
|
||||
```c
|
||||
for (int i = n - 1; i >= 0; i--) { }
|
||||
```
|
||||
|
||||
**Step by 2:**
|
||||
```c
|
||||
for (int i = 0; i < n; i += 2) { }
|
||||
```
|
||||
|
||||
**Iterate array:**
|
||||
```c
|
||||
for (int i = 0; i < arraySize; i++) {
|
||||
printf("%d\n", array[i]);
|
||||
}
|
||||
```
|
||||
|
||||
**Iterate with pointer:**
|
||||
```c
|
||||
for (int *p = array; p < array + arraySize; p++) {
|
||||
printf("%d\n", *p);
|
||||
}
|
||||
```
|
||||
|
||||
### 5.10 Key Concepts Learned
|
||||
- ✅ while loops
|
||||
- ✅ do-while loops
|
||||
- ✅ for loops
|
||||
- ✅ break statement
|
||||
- ✅ continue statement
|
||||
- ✅ Nested loops
|
||||
- ✅ Infinite loops
|
||||
- ✅ Common loop patterns
|
||||
|
||||
---
|
||||
|
||||
## Chapter 6: Functions {#chapter-6}
|
||||
|
||||
### 3.1 Function Basics
|
||||
|
||||
|
|
|
|||
661
docs/14_bit_manipulation.md
Normal file
661
docs/14_bit_manipulation.md
Normal file
|
|
@ -0,0 +1,661 @@
|
|||
# Chapter 14: Bit Manipulation in C
|
||||
|
||||
## Complete Guide with Clay Library Examples
|
||||
|
||||
---
|
||||
|
||||
## 14.1 Binary Number System
|
||||
|
||||
Understanding binary is essential for bit manipulation:
|
||||
|
||||
```c
|
||||
// Decimal vs Binary
|
||||
0 = 0000
|
||||
1 = 0001
|
||||
2 = 0010
|
||||
3 = 0011
|
||||
4 = 0100
|
||||
5 = 0101
|
||||
6 = 0110
|
||||
7 = 0111
|
||||
8 = 1000
|
||||
```
|
||||
|
||||
### Converting Binary to Decimal
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int binaryToDecimal(int binary) {
|
||||
int decimal = 0, base = 1;
|
||||
while (binary > 0) {
|
||||
int lastDigit = binary % 10;
|
||||
decimal += lastDigit * base;
|
||||
base *= 2;
|
||||
binary /= 10;
|
||||
}
|
||||
return decimal;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
printf("%d\n", binaryToDecimal(1010)); // 10
|
||||
printf("%d\n", binaryToDecimal(1111)); // 15
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.2 Bitwise Operators
|
||||
|
||||
### AND Operator (&)
|
||||
|
||||
```c
|
||||
// Both bits must be 1
|
||||
int a = 5; // 0101
|
||||
int b = 3; // 0011
|
||||
int c = a & b; // 0001 = 1
|
||||
|
||||
// Check if number is even
|
||||
int isEven(int n) {
|
||||
return (n & 1) == 0; // Check if last bit is 0
|
||||
}
|
||||
```
|
||||
|
||||
**Clay Example:**
|
||||
```c
|
||||
// Check if corner radius flag is set
|
||||
typedef enum {
|
||||
CLAY_CORNER_RADIUS_TOP_LEFT = 1 << 0, // 0001
|
||||
CLAY_CORNER_RADIUS_TOP_RIGHT = 1 << 1, // 0010
|
||||
CLAY_CORNER_RADIUS_BOTTOM_LEFT = 1 << 2, // 0100
|
||||
CLAY_CORNER_RADIUS_BOTTOM_RIGHT = 1 << 3 // 1000
|
||||
} Clay_CornerRadiusSet;
|
||||
|
||||
// Check if top-left corner has radius
|
||||
if (flags & CLAY_CORNER_RADIUS_TOP_LEFT) {
|
||||
// Top left corner has radius
|
||||
}
|
||||
```
|
||||
|
||||
### OR Operator (|)
|
||||
|
||||
```c
|
||||
// At least one bit must be 1
|
||||
int a = 5; // 0101
|
||||
int b = 3; // 0011
|
||||
int c = a | b; // 0111 = 7
|
||||
|
||||
// Set specific bit
|
||||
int setBit(int num, int pos) {
|
||||
return num | (1 << pos);
|
||||
}
|
||||
```
|
||||
|
||||
**Clay Example:**
|
||||
```c
|
||||
// Combine multiple corner radius flags
|
||||
int flags = CLAY_CORNER_RADIUS_TOP_LEFT |
|
||||
CLAY_CORNER_RADIUS_TOP_RIGHT; // 0011 = both top corners
|
||||
|
||||
// Add another flag
|
||||
flags |= CLAY_CORNER_RADIUS_BOTTOM_LEFT; // Now 0111 = three corners
|
||||
```
|
||||
|
||||
### XOR Operator (^)
|
||||
|
||||
```c
|
||||
// Bits must be different
|
||||
int a = 5; // 0101
|
||||
int b = 3; // 0011
|
||||
int c = a ^ b; // 0110 = 6
|
||||
|
||||
// Swap two numbers without temp variable
|
||||
void swap(int *a, int *b) {
|
||||
*a = *a ^ *b;
|
||||
*b = *a ^ *b;
|
||||
*a = *a ^ *b;
|
||||
}
|
||||
```
|
||||
|
||||
### NOT Operator (~)
|
||||
|
||||
```c
|
||||
// Inverts all bits
|
||||
int a = 5; // 00000101
|
||||
int b = ~a; // 11111010 (in 8-bit)
|
||||
|
||||
// Clear specific bit
|
||||
int clearBit(int num, int pos) {
|
||||
return num & ~(1 << pos);
|
||||
}
|
||||
```
|
||||
|
||||
### Left Shift (<<)
|
||||
|
||||
```c
|
||||
// Multiply by 2^n
|
||||
int a = 5; // 0101
|
||||
int b = a << 1; // 1010 = 10 (multiply by 2)
|
||||
int c = a << 2; // 10100 = 20 (multiply by 4)
|
||||
|
||||
// Fast power of 2
|
||||
int powerOf2(int n) {
|
||||
return 1 << n; // 2^n
|
||||
}
|
||||
```
|
||||
|
||||
**Clay Example:**
|
||||
```c
|
||||
// Define bit flags with left shift
|
||||
typedef enum {
|
||||
CLAY_CORNER_RADIUS_TOP_LEFT = 1 << 0, // 1
|
||||
CLAY_CORNER_RADIUS_TOP_RIGHT = 1 << 1, // 2
|
||||
CLAY_CORNER_RADIUS_BOTTOM_LEFT = 1 << 2, // 4
|
||||
CLAY_CORNER_RADIUS_BOTTOM_RIGHT = 1 << 3 // 8
|
||||
} Clay_CornerRadiusSet;
|
||||
```
|
||||
|
||||
### Right Shift (>>)
|
||||
|
||||
```c
|
||||
// Divide by 2^n
|
||||
int a = 20; // 10100
|
||||
int b = a >> 1; // 01010 = 10 (divide by 2)
|
||||
int c = a >> 2; // 00101 = 5 (divide by 4)
|
||||
|
||||
// Extract specific bits
|
||||
int getBits(int num, int start, int count) {
|
||||
return (num >> start) & ((1 << count) - 1);
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.3 Common Bit Operations
|
||||
|
||||
### Check if Bit is Set
|
||||
|
||||
```c
|
||||
int isBitSet(int num, int pos) {
|
||||
return (num & (1 << pos)) != 0;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
int num = 5; // 0101
|
||||
printf("%d\n", isBitSet(num, 0)); // 1 (bit 0 is set)
|
||||
printf("%d\n", isBitSet(num, 1)); // 0 (bit 1 is not set)
|
||||
printf("%d\n", isBitSet(num, 2)); // 1 (bit 2 is set)
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Set a Bit
|
||||
|
||||
```c
|
||||
int setBit(int num, int pos) {
|
||||
return num | (1 << pos);
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
int num = 5; // 0101
|
||||
num = setBit(num, 1); // 0111 = 7
|
||||
printf("%d\n", num);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Clear a Bit
|
||||
|
||||
```c
|
||||
int clearBit(int num, int pos) {
|
||||
return num & ~(1 << pos);
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
int num = 7; // 0111
|
||||
num = clearBit(num, 1); // 0101 = 5
|
||||
printf("%d\n", num);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Toggle a Bit
|
||||
|
||||
```c
|
||||
int toggleBit(int num, int pos) {
|
||||
return num ^ (1 << pos);
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
int num = 5; // 0101
|
||||
num = toggleBit(num, 1); // 0111 = 7
|
||||
num = toggleBit(num, 1); // 0101 = 5 (back to original)
|
||||
printf("%d\n", num);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.4 Bit Masks
|
||||
|
||||
Masks select specific bits:
|
||||
|
||||
```c
|
||||
// Extract RGB components from 32-bit color
|
||||
typedef struct {
|
||||
uint32_t color; // 0xAARRGGBB
|
||||
} Color;
|
||||
|
||||
uint8_t getRed(Color c) {
|
||||
return (c.color >> 16) & 0xFF; // Mask: 0x00FF0000
|
||||
}
|
||||
|
||||
uint8_t getGreen(Color c) {
|
||||
return (c.color >> 8) & 0xFF; // Mask: 0x0000FF00
|
||||
}
|
||||
|
||||
uint8_t getBlue(Color c) {
|
||||
return c.color & 0xFF; // Mask: 0x000000FF
|
||||
}
|
||||
|
||||
uint8_t getAlpha(Color c) {
|
||||
return (c.color >> 24) & 0xFF; // Mask: 0xFF000000
|
||||
}
|
||||
|
||||
uint32_t makeColor(uint8_t r, uint8_t g, uint8_t b, uint8_t a) {
|
||||
return ((uint32_t)a << 24) |
|
||||
((uint32_t)r << 16) |
|
||||
((uint32_t)g << 8) |
|
||||
(uint32_t)b;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay Example (conceptual):**
|
||||
```c
|
||||
// Clay uses float colors, but shows similar concepts
|
||||
typedef struct {
|
||||
float r, g, b, a;
|
||||
} Clay_Color;
|
||||
|
||||
// If Clay used packed colors:
|
||||
uint32_t packColor(Clay_Color c) {
|
||||
uint8_t r = (uint8_t)(c.r * 255);
|
||||
uint8_t g = (uint8_t)(c.g * 255);
|
||||
uint8_t b = (uint8_t)(c.b * 255);
|
||||
uint8_t a = (uint8_t)(c.a * 255);
|
||||
return (a << 24) | (r << 16) | (g << 8) | b;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.5 Bit Fields in Structs
|
||||
|
||||
Pack multiple values efficiently:
|
||||
|
||||
```c
|
||||
struct Flags {
|
||||
unsigned int isVisible : 1; // 1 bit
|
||||
unsigned int isEnabled : 1; // 1 bit
|
||||
unsigned int priority : 3; // 3 bits (0-7)
|
||||
unsigned int id : 11; // 11 bits
|
||||
}; // Total: 16 bits = 2 bytes
|
||||
|
||||
int main(void) {
|
||||
struct Flags f = {0};
|
||||
f.isVisible = 1;
|
||||
f.isEnabled = 1;
|
||||
f.priority = 5;
|
||||
f.id = 1024;
|
||||
|
||||
printf("Size: %zu bytes\n", sizeof(f)); // 2 or 4 (compiler dependent)
|
||||
printf("Priority: %u\n", f.priority);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay Example (conceptual):**
|
||||
```c
|
||||
// Clay could use bit fields for layout flags
|
||||
typedef struct {
|
||||
uint32_t layoutDirection : 1; // 0 = horizontal, 1 = vertical
|
||||
uint32_t wrapChildren : 1; // Wrap to next line
|
||||
uint32_t alignmentX : 2; // 0-3 for alignment options
|
||||
uint32_t alignmentY : 2;
|
||||
uint32_t reserved : 26; // Future use
|
||||
} Clay_LayoutFlags;
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.6 Counting Set Bits
|
||||
|
||||
### Method 1: Loop
|
||||
|
||||
```c
|
||||
int countSetBits(int n) {
|
||||
int count = 0;
|
||||
while (n > 0) {
|
||||
count += n & 1; // Add last bit
|
||||
n >>= 1; // Shift right
|
||||
}
|
||||
return count;
|
||||
}
|
||||
```
|
||||
|
||||
### Method 2: Brian Kernighan's Algorithm
|
||||
|
||||
```c
|
||||
int countSetBits(int n) {
|
||||
int count = 0;
|
||||
while (n > 0) {
|
||||
n &= (n - 1); // Clear rightmost set bit
|
||||
count++;
|
||||
}
|
||||
return count;
|
||||
}
|
||||
|
||||
// Example: n = 12 (1100)
|
||||
// 1100 & 1011 = 1000 (count = 1)
|
||||
// 1000 & 0111 = 0000 (count = 2)
|
||||
```
|
||||
|
||||
### Method 3: Lookup Table
|
||||
|
||||
```c
|
||||
// Precomputed table for 4-bit numbers
|
||||
int table[16] = {
|
||||
0, 1, 1, 2, 1, 2, 2, 3,
|
||||
1, 2, 2, 3, 2, 3, 3, 4
|
||||
};
|
||||
|
||||
int countSetBits(int n) {
|
||||
int count = 0;
|
||||
while (n > 0) {
|
||||
count += table[n & 0xF]; // Count 4 bits at a time
|
||||
n >>= 4;
|
||||
}
|
||||
return count;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.7 Power of Two
|
||||
|
||||
### Check if Power of 2
|
||||
|
||||
```c
|
||||
int isPowerOfTwo(int n) {
|
||||
return n > 0 && (n & (n - 1)) == 0;
|
||||
}
|
||||
|
||||
// Examples:
|
||||
// 4 (100) & 3 (011) = 0 → true
|
||||
// 5 (101) & 4 (100) = 4 → false
|
||||
// 8 (1000) & 7 (0111) = 0 → true
|
||||
```
|
||||
|
||||
### Next Power of 2
|
||||
|
||||
```c
|
||||
int nextPowerOfTwo(int n) {
|
||||
if (n <= 0) return 1;
|
||||
n--;
|
||||
n |= n >> 1;
|
||||
n |= n >> 2;
|
||||
n |= n >> 4;
|
||||
n |= n >> 8;
|
||||
n |= n >> 16;
|
||||
return n + 1;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
printf("%d\n", nextPowerOfTwo(5)); // 8
|
||||
printf("%d\n", nextPowerOfTwo(17)); // 32
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.8 Swap Values
|
||||
|
||||
### Without Temporary Variable
|
||||
|
||||
```c
|
||||
void swap(int *a, int *b) {
|
||||
if (a != b) { // Must check for same address
|
||||
*a ^= *b;
|
||||
*b ^= *a;
|
||||
*a ^= *b;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### Swap Nibbles (4-bit)
|
||||
|
||||
```c
|
||||
int swapNibbles(int n) {
|
||||
return ((n & 0x0F) << 4) | ((n & 0xF0) >> 4);
|
||||
}
|
||||
|
||||
// Example: 0x5A → 0xA5
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.9 Reverse Bits
|
||||
|
||||
```c
|
||||
uint32_t reverseBits(uint32_t n) {
|
||||
uint32_t result = 0;
|
||||
for (int i = 0; i < 32; i++) {
|
||||
result <<= 1; // Shift result left
|
||||
result |= (n & 1); // Add rightmost bit of n
|
||||
n >>= 1; // Shift n right
|
||||
}
|
||||
return result;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.10 Parity
|
||||
|
||||
Check if number of set bits is even or odd:
|
||||
|
||||
```c
|
||||
int getParity(int n) {
|
||||
int parity = 0;
|
||||
while (n > 0) {
|
||||
parity ^= (n & 1);
|
||||
n >>= 1;
|
||||
}
|
||||
return parity; // 0 = even, 1 = odd
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.11 Gray Code
|
||||
|
||||
Convert between binary and Gray code:
|
||||
|
||||
```c
|
||||
// Binary to Gray
|
||||
int binaryToGray(int n) {
|
||||
return n ^ (n >> 1);
|
||||
}
|
||||
|
||||
// Gray to Binary
|
||||
int grayToBinary(int n) {
|
||||
int binary = 0;
|
||||
while (n > 0) {
|
||||
binary ^= n;
|
||||
n >>= 1;
|
||||
}
|
||||
return binary;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.12 Position of Rightmost Set Bit
|
||||
|
||||
```c
|
||||
int rightmostSetBit(int n) {
|
||||
return n & ~(n - 1);
|
||||
}
|
||||
|
||||
// Example: 12 (1100)
|
||||
// Returns: 4 (0100) - position of rightmost 1
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.13 Toggle All Bits After Rightmost Set Bit
|
||||
|
||||
```c
|
||||
int toggleAfterRightmost(int n) {
|
||||
return n ^ (n - 1);
|
||||
}
|
||||
|
||||
// Example: 12 (1100)
|
||||
// Returns: 15 (1111)
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.14 Extract and Set Bit Ranges
|
||||
|
||||
```c
|
||||
// Extract bits from position p to p+n
|
||||
int extractBits(int num, int p, int n) {
|
||||
return (num >> p) & ((1 << n) - 1);
|
||||
}
|
||||
|
||||
// Set bits from position p to p+n
|
||||
int setBits(int num, int p, int n, int value) {
|
||||
int mask = ((1 << n) - 1) << p;
|
||||
return (num & ~mask) | ((value << p) & mask);
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.15 Practical Applications in Clay
|
||||
|
||||
### Bit Flags for UI State
|
||||
|
||||
```c
|
||||
typedef enum {
|
||||
CLAY_ELEMENT_VISIBLE = 1 << 0, // 0x01
|
||||
CLAY_ELEMENT_ENABLED = 1 << 1, // 0x02
|
||||
CLAY_ELEMENT_FOCUSED = 1 << 2, // 0x04
|
||||
CLAY_ELEMENT_HOVERED = 1 << 3, // 0x08
|
||||
CLAY_ELEMENT_PRESSED = 1 << 4, // 0x10
|
||||
CLAY_ELEMENT_SELECTED = 1 << 5, // 0x20
|
||||
CLAY_ELEMENT_DISABLED = 1 << 6, // 0x40
|
||||
CLAY_ELEMENT_HIDDEN = 1 << 7 // 0x80
|
||||
} Clay_ElementFlags;
|
||||
|
||||
typedef struct {
|
||||
uint32_t flags;
|
||||
} Clay_Element;
|
||||
|
||||
// Check state
|
||||
int isVisible(Clay_Element *el) {
|
||||
return (el->flags & CLAY_ELEMENT_VISIBLE) != 0;
|
||||
}
|
||||
|
||||
// Set state
|
||||
void setVisible(Clay_Element *el, int visible) {
|
||||
if (visible) {
|
||||
el->flags |= CLAY_ELEMENT_VISIBLE; // Set bit
|
||||
} else {
|
||||
el->flags &= ~CLAY_ELEMENT_VISIBLE; // Clear bit
|
||||
}
|
||||
}
|
||||
|
||||
// Toggle state
|
||||
void toggleVisible(Clay_Element *el) {
|
||||
el->flags ^= CLAY_ELEMENT_VISIBLE;
|
||||
}
|
||||
|
||||
// Multiple states at once
|
||||
void setInteractive(Clay_Element *el) {
|
||||
el->flags |= (CLAY_ELEMENT_VISIBLE |
|
||||
CLAY_ELEMENT_ENABLED);
|
||||
}
|
||||
```
|
||||
|
||||
### Optimized Hash Functions
|
||||
|
||||
```c
|
||||
// Clay uses hashing for element lookup
|
||||
uint32_t hashString(const char *str, size_t length) {
|
||||
uint32_t hash = 0;
|
||||
for (size_t i = 0; i < length; i++) {
|
||||
hash = (hash << 5) - hash + str[i]; // hash * 31 + c
|
||||
// Using bit shift instead of multiply
|
||||
}
|
||||
return hash;
|
||||
}
|
||||
```
|
||||
|
||||
### Memory Alignment
|
||||
|
||||
```c
|
||||
// Align size to power of 2
|
||||
size_t alignSize(size_t size, size_t alignment) {
|
||||
return (size + alignment - 1) & ~(alignment - 1);
|
||||
}
|
||||
|
||||
// Example: align to 16 bytes
|
||||
// size = 25
|
||||
// (25 + 15) & ~15 = 40 & 0xFFFFFFF0 = 32
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 14.16 Performance Tips
|
||||
|
||||
**Use bit operations for:**
|
||||
- ✅ Powers of 2 multiplication/division
|
||||
- ✅ Flag checks (faster than booleans)
|
||||
- ✅ Color packing/unpacking
|
||||
- ✅ Hash functions
|
||||
- ✅ Alignment calculations
|
||||
|
||||
**Avoid for:**
|
||||
- ❌ Regular arithmetic (compiler optimizes)
|
||||
- ❌ Readability-critical code
|
||||
- ❌ Floating-point operations
|
||||
|
||||
---
|
||||
|
||||
## 14.17 Key Concepts Learned
|
||||
- ✅ Bitwise operators: &, |, ^, ~, <<, >>
|
||||
- ✅ Bit manipulation: set, clear, toggle, check
|
||||
- ✅ Bit masks and extraction
|
||||
- ✅ Bit fields in structs
|
||||
- ✅ Counting set bits
|
||||
- ✅ Power of 2 operations
|
||||
- ✅ Practical applications in Clay
|
||||
- ✅ Performance considerations
|
||||
|
||||
---
|
||||
|
||||
## Practice Exercises
|
||||
|
||||
1. Write a function to count trailing zeros in a number
|
||||
2. Implement bitwise rotation (rotate left/right)
|
||||
3. Find the only non-duplicate number in an array (all others appear twice)
|
||||
4. Swap all odd and even bits in a number
|
||||
5. Add two numbers without using + operator
|
||||
6. Implement a bit vector data structure
|
||||
7. Create a compact permission system using bit flags
|
||||
8. Write efficient popcount for 64-bit numbers
|
||||
727
docs/21_standard_library.md
Normal file
727
docs/21_standard_library.md
Normal file
|
|
@ -0,0 +1,727 @@
|
|||
# Chapter 21: C Standard Library Basics
|
||||
|
||||
## Complete Guide with Clay Library Examples
|
||||
|
||||
---
|
||||
|
||||
## 21.1 What is the C Standard Library?
|
||||
|
||||
The C Standard Library provides essential functions for:
|
||||
- Input/Output (`stdio.h`)
|
||||
- String manipulation (`string.h`)
|
||||
- Memory management (`stdlib.h`)
|
||||
- Math operations (`math.h`)
|
||||
- Character handling (`ctype.h`)
|
||||
- Time/Date (`time.h`)
|
||||
|
||||
**Clay's Approach:** Clay is **zero-dependency** - it doesn't use the standard library! This shows how to write portable C without stdlib.
|
||||
|
||||
---
|
||||
|
||||
## 21.2 stdio.h - Input/Output
|
||||
|
||||
### Printf Family
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
// Basic printf
|
||||
printf("Hello, World!\n");
|
||||
|
||||
// Format specifiers
|
||||
int age = 25;
|
||||
float height = 5.9f;
|
||||
char grade = 'A';
|
||||
|
||||
printf("Age: %d\n", age); // int
|
||||
printf("Height: %.2f\n", height); // float with 2 decimals
|
||||
printf("Grade: %c\n", grade); // char
|
||||
printf("Hex: %x\n", 255); // hexadecimal (ff)
|
||||
printf("Pointer: %p\n", (void*)&age); // pointer address
|
||||
|
||||
// Width and padding
|
||||
printf("%5d\n", 42); // " 42" (right-aligned)
|
||||
printf("%-5d\n", 42); // "42 " (left-aligned)
|
||||
printf("%05d\n", 42); // "00042" (zero-padded)
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Sprintf - Format to String
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
char buffer[100];
|
||||
|
||||
int x = 10, y = 20;
|
||||
sprintf(buffer, "Point: (%d, %d)", x, y);
|
||||
printf("%s\n", buffer); // "Point: (10, 20)"
|
||||
|
||||
// Safer version with size limit
|
||||
snprintf(buffer, sizeof(buffer), "Value: %d", 42);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Scanf Family
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
int age;
|
||||
float height;
|
||||
char name[50];
|
||||
|
||||
printf("Enter age: ");
|
||||
scanf("%d", &age); // Note: address-of operator!
|
||||
|
||||
printf("Enter height: ");
|
||||
scanf("%f", &height);
|
||||
|
||||
printf("Enter name: ");
|
||||
scanf("%49s", name); // Limit input to avoid overflow
|
||||
|
||||
printf("Name: %s, Age: %d, Height: %.1f\n", name, age, height);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### File Operations
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file;
|
||||
|
||||
// Write to file
|
||||
file = fopen("output.txt", "w");
|
||||
if (file == NULL) {
|
||||
printf("Error opening file!\n");
|
||||
return 1;
|
||||
}
|
||||
fprintf(file, "Hello, File!\n");
|
||||
fclose(file);
|
||||
|
||||
// Read from file
|
||||
file = fopen("output.txt", "r");
|
||||
if (file != NULL) {
|
||||
char buffer[100];
|
||||
while (fgets(buffer, sizeof(buffer), file) != NULL) {
|
||||
printf("%s", buffer);
|
||||
}
|
||||
fclose(file);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay doesn't use stdio.h** - it's renderer-agnostic and doesn't handle file I/O internally.
|
||||
|
||||
---
|
||||
|
||||
## 21.3 stdlib.h - General Utilities
|
||||
|
||||
### Memory Allocation
|
||||
|
||||
```c
|
||||
#include <stdlib.h>
|
||||
|
||||
int main(void) {
|
||||
// Allocate memory
|
||||
int *arr = (int*)malloc(10 * sizeof(int));
|
||||
if (arr == NULL) {
|
||||
printf("Memory allocation failed!\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
// Use array
|
||||
for (int i = 0; i < 10; i++) {
|
||||
arr[i] = i * 2;
|
||||
}
|
||||
|
||||
// Resize array
|
||||
arr = (int*)realloc(arr, 20 * sizeof(int));
|
||||
|
||||
// Free memory
|
||||
free(arr);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay's Approach:** Uses custom arena allocators instead of malloc/free!
|
||||
|
||||
```c
|
||||
// Clay's arena allocator (from clay.h)
|
||||
typedef struct {
|
||||
size_t capacity;
|
||||
size_t nextAllocation;
|
||||
char *memory;
|
||||
} Clay_Arena;
|
||||
|
||||
void* Clay__AllocateArena(Clay_Arena *arena, size_t size) {
|
||||
if (arena->nextAllocation + size <= arena->capacity) {
|
||||
void *ptr = arena->memory + arena->nextAllocation;
|
||||
arena->nextAllocation += size;
|
||||
return ptr;
|
||||
}
|
||||
return NULL; // Out of memory
|
||||
}
|
||||
```
|
||||
|
||||
### String to Number Conversion
|
||||
|
||||
```c
|
||||
#include <stdlib.h>
|
||||
|
||||
int main(void) {
|
||||
// String to integer
|
||||
int num1 = atoi("123"); // 123
|
||||
long num2 = atol("123456789"); // 123456789
|
||||
long long num3 = atoll("9999999999"); // 9999999999
|
||||
|
||||
// String to float
|
||||
double num4 = atof("3.14159"); // 3.14159
|
||||
|
||||
// More robust conversion with error checking
|
||||
char *endptr;
|
||||
long value = strtol("123abc", &endptr, 10);
|
||||
if (*endptr != '\0') {
|
||||
printf("Invalid number: stopped at '%s'\n", endptr);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Random Numbers
|
||||
|
||||
```c
|
||||
#include <stdlib.h>
|
||||
#include <time.h>
|
||||
|
||||
int main(void) {
|
||||
// Seed random number generator
|
||||
srand(time(NULL));
|
||||
|
||||
// Generate random numbers
|
||||
for (int i = 0; i < 5; i++) {
|
||||
int random = rand(); // 0 to RAND_MAX
|
||||
printf("%d\n", random);
|
||||
}
|
||||
|
||||
// Random in range [min, max]
|
||||
int min = 1, max = 100;
|
||||
int randomInRange = min + rand() % (max - min + 1);
|
||||
printf("Random (1-100): %d\n", randomInRange);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Program Termination
|
||||
|
||||
```c
|
||||
#include <stdlib.h>
|
||||
|
||||
void cleanup(void) {
|
||||
printf("Cleaning up...\n");
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
// Register cleanup function
|
||||
atexit(cleanup);
|
||||
|
||||
// Normal exit
|
||||
// exit(0); // Success
|
||||
// exit(1); // Failure
|
||||
|
||||
// Abnormal termination
|
||||
// abort(); // Immediate termination
|
||||
|
||||
return 0;
|
||||
} // cleanup() called automatically
|
||||
```
|
||||
|
||||
### Environment Variables
|
||||
|
||||
```c
|
||||
#include <stdlib.h>
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
// Get environment variable
|
||||
char *path = getenv("PATH");
|
||||
if (path != NULL) {
|
||||
printf("PATH: %s\n", path);
|
||||
}
|
||||
|
||||
char *home = getenv("HOME");
|
||||
if (home != NULL) {
|
||||
printf("HOME: %s\n", home);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 21.4 string.h - String Manipulation
|
||||
|
||||
### String Length
|
||||
|
||||
```c
|
||||
#include <string.h>
|
||||
|
||||
int main(void) {
|
||||
char str[] = "Hello";
|
||||
size_t len = strlen(str); // 5
|
||||
printf("Length: %zu\n", len);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay's Implementation** (from clay.h):
|
||||
```c
|
||||
// Clay uses explicit length, no strlen needed
|
||||
typedef struct {
|
||||
int32_t length; // Length stored directly!
|
||||
const char *chars;
|
||||
} Clay_String;
|
||||
|
||||
// O(1) length access
|
||||
int getLength(Clay_String *str) {
|
||||
return str->length; // No need to count!
|
||||
}
|
||||
```
|
||||
|
||||
### String Copy
|
||||
|
||||
```c
|
||||
#include <string.h>
|
||||
|
||||
int main(void) {
|
||||
char src[] = "Hello";
|
||||
char dest[20];
|
||||
|
||||
// Copy string
|
||||
strcpy(dest, src);
|
||||
|
||||
// Copy with size limit (safer)
|
||||
strncpy(dest, src, sizeof(dest) - 1);
|
||||
dest[sizeof(dest) - 1] = '\0'; // Ensure null termination
|
||||
|
||||
printf("%s\n", dest);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### String Concatenation
|
||||
|
||||
```c
|
||||
#include <string.h>
|
||||
|
||||
int main(void) {
|
||||
char str[50] = "Hello";
|
||||
|
||||
// Concatenate
|
||||
strcat(str, " World"); // "Hello World"
|
||||
|
||||
// Concatenate with limit (safer)
|
||||
strncat(str, "!", sizeof(str) - strlen(str) - 1);
|
||||
|
||||
printf("%s\n", str);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### String Comparison
|
||||
|
||||
```c
|
||||
#include <string.h>
|
||||
|
||||
int main(void) {
|
||||
char str1[] = "Apple";
|
||||
char str2[] = "Banana";
|
||||
|
||||
// Compare strings
|
||||
int result = strcmp(str1, str2);
|
||||
if (result < 0) {
|
||||
printf("%s comes before %s\n", str1, str2);
|
||||
} else if (result > 0) {
|
||||
printf("%s comes after %s\n", str1, str2);
|
||||
} else {
|
||||
printf("Strings are equal\n");
|
||||
}
|
||||
|
||||
// Compare n characters
|
||||
if (strncmp(str1, str2, 3) == 0) {
|
||||
printf("First 3 characters match\n");
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Memory Operations
|
||||
|
||||
```c
|
||||
#include <string.h>
|
||||
|
||||
int main(void) {
|
||||
char buffer[20];
|
||||
|
||||
// Set memory to value
|
||||
memset(buffer, 'A', 10);
|
||||
buffer[10] = '\0';
|
||||
printf("%s\n", buffer); // "AAAAAAAAAA"
|
||||
|
||||
// Copy memory
|
||||
char src[] = "Hello";
|
||||
char dest[20];
|
||||
memcpy(dest, src, strlen(src) + 1); // Include \0
|
||||
|
||||
// Move memory (handles overlapping regions)
|
||||
memmove(dest + 2, dest, strlen(dest) + 1); // Shift right
|
||||
printf("%s\n", dest); // "HeHello"
|
||||
|
||||
// Compare memory
|
||||
if (memcmp(src, dest, 5) == 0) {
|
||||
printf("Memory regions match\n");
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay's Approach:**
|
||||
```c
|
||||
// Clay uses custom memory functions when needed
|
||||
static inline void Clay__MemoryCopy(
|
||||
void *dest,
|
||||
const void *src,
|
||||
size_t size
|
||||
) {
|
||||
char *d = (char*)dest;
|
||||
const char *s = (const char*)src;
|
||||
for (size_t i = 0; i < size; i++) {
|
||||
d[i] = s[i];
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 21.5 math.h - Mathematical Functions
|
||||
|
||||
```c
|
||||
#include <math.h>
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
// Power and roots
|
||||
printf("2^3 = %.0f\n", pow(2, 3)); // 8
|
||||
printf("sqrt(16) = %.0f\n", sqrt(16)); // 4
|
||||
printf("cbrt(27) = %.0f\n", cbrt(27)); // 3
|
||||
|
||||
// Trigonometry
|
||||
printf("sin(π/2) = %.1f\n", sin(M_PI / 2)); // 1.0
|
||||
printf("cos(0) = %.1f\n", cos(0)); // 1.0
|
||||
printf("tan(π/4) = %.1f\n", tan(M_PI / 4)); // 1.0
|
||||
|
||||
// Rounding
|
||||
printf("ceil(3.2) = %.0f\n", ceil(3.2)); // 4
|
||||
printf("floor(3.8) = %.0f\n", floor(3.8)); // 3
|
||||
printf("round(3.5) = %.0f\n", round(3.5)); // 4
|
||||
|
||||
// Absolute value
|
||||
printf("fabs(-5.5) = %.1f\n", fabs(-5.5)); // 5.5
|
||||
printf("abs(-5) = %d\n", abs(-5)); // 5
|
||||
|
||||
// Logarithms
|
||||
printf("log(e) = %.1f\n", log(M_E)); // 1.0
|
||||
printf("log10(100) = %.0f\n", log10(100)); // 2
|
||||
|
||||
// Exponential
|
||||
printf("exp(1) = %.2f\n", exp(1)); // 2.72 (e)
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay's Implementation:**
|
||||
```c
|
||||
// Clay implements its own min/max (no stdlib needed)
|
||||
static inline float Clay__Min(float a, float b) {
|
||||
return a < b ? a : b;
|
||||
}
|
||||
|
||||
static inline float Clay__Max(float a, float b) {
|
||||
return a > b ? a : b;
|
||||
}
|
||||
|
||||
static inline float Clay__Clamp(float value, float min, float max) {
|
||||
return Clay__Max(min, Clay__Min(value, max));
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 21.6 ctype.h - Character Handling
|
||||
|
||||
```c
|
||||
#include <ctype.h>
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
char ch = 'A';
|
||||
|
||||
// Character testing
|
||||
if (isalpha(ch)) printf("Letter\n");
|
||||
if (isdigit(ch)) printf("Digit\n");
|
||||
if (isalnum(ch)) printf("Alphanumeric\n");
|
||||
if (isupper(ch)) printf("Uppercase\n");
|
||||
if (islower(ch)) printf("Lowercase\n");
|
||||
if (isspace(ch)) printf("Whitespace\n");
|
||||
if (ispunct(ch)) printf("Punctuation\n");
|
||||
|
||||
// Character conversion
|
||||
printf("Upper: %c\n", toupper('a')); // 'A'
|
||||
printf("Lower: %c\n", tolower('A')); // 'a'
|
||||
|
||||
// Practical example: validate identifier
|
||||
int isValidIdentifier(const char *str) {
|
||||
if (!isalpha(str[0]) && str[0] != '_') {
|
||||
return 0; // Must start with letter or _
|
||||
}
|
||||
for (int i = 1; str[i] != '\0'; i++) {
|
||||
if (!isalnum(str[i]) && str[i] != '_') {
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
return 1;
|
||||
}
|
||||
|
||||
printf("valid_name: %d\n", isValidIdentifier("valid_name")); // 1
|
||||
printf("123invalid: %d\n", isValidIdentifier("123invalid")); // 0
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 21.7 time.h - Time and Date
|
||||
|
||||
```c
|
||||
#include <time.h>
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
// Current time
|
||||
time_t now = time(NULL);
|
||||
printf("Seconds since epoch: %ld\n", now);
|
||||
|
||||
// Convert to readable format
|
||||
struct tm *timeinfo = localtime(&now);
|
||||
printf("Current time: %s", asctime(timeinfo));
|
||||
|
||||
// Format time
|
||||
char buffer[80];
|
||||
strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", timeinfo);
|
||||
printf("Formatted: %s\n", buffer);
|
||||
|
||||
// Measure execution time
|
||||
clock_t start = clock();
|
||||
|
||||
// Do some work
|
||||
for (int i = 0; i < 1000000; i++) {
|
||||
// Busy work
|
||||
}
|
||||
|
||||
clock_t end = clock();
|
||||
double cpu_time = ((double)(end - start)) / CLOCKS_PER_SEC;
|
||||
printf("CPU time: %.6f seconds\n", cpu_time);
|
||||
|
||||
// Sleep (POSIX)
|
||||
// sleep(1); // Sleep 1 second
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 21.8 assert.h - Debugging
|
||||
|
||||
```c
|
||||
#include <assert.h>
|
||||
#include <stdio.h>
|
||||
|
||||
int divide(int a, int b) {
|
||||
assert(b != 0); // Crash if b is 0 (in debug builds)
|
||||
return a / b;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
int result = divide(10, 2); // OK
|
||||
printf("Result: %d\n", result);
|
||||
|
||||
// result = divide(10, 0); // Crashes with error message
|
||||
|
||||
// Disable asserts in release
|
||||
// Compile with: gcc -DNDEBUG program.c
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay's Approach:**
|
||||
```c
|
||||
// Clay has custom error handling
|
||||
#define CLAY__ASSERT(condition) \
|
||||
if (!(condition)) { \
|
||||
Clay__ErrorHandler(...); \
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 21.9 stdint.h - Fixed-Width Integers
|
||||
|
||||
```c
|
||||
#include <stdint.h>
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
// Exact-width integers
|
||||
int8_t i8 = 127; // -128 to 127
|
||||
uint8_t u8 = 255; // 0 to 255
|
||||
int16_t i16 = 32767; // -32768 to 32767
|
||||
uint16_t u16 = 65535; // 0 to 65535
|
||||
int32_t i32 = 2147483647;
|
||||
uint32_t u32 = 4294967295;
|
||||
int64_t i64 = 9223372036854775807;
|
||||
uint64_t u64 = 18446744073709551615ULL;
|
||||
|
||||
// Pointer-sized integers
|
||||
intptr_t iptr; // Can hold pointer
|
||||
uintptr_t uptr;
|
||||
|
||||
// Fast types (at least N bits)
|
||||
int_fast32_t fast32; // Fast 32-bit (may be 64-bit)
|
||||
int_least32_t least32; // At least 32-bit (may be 32+)
|
||||
|
||||
// Print with proper format specifiers
|
||||
printf("int32: %" PRId32 "\n", i32);
|
||||
printf("uint64: %" PRIu64 "\n", u64);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Clay uses fixed-width types extensively:**
|
||||
```c
|
||||
typedef struct {
|
||||
int32_t capacity; // Exactly 32 bits
|
||||
int32_t length;
|
||||
uint32_t *internalArray;
|
||||
} Clay__int32_tArray;
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 21.10 stdbool.h - Boolean Type
|
||||
|
||||
```c
|
||||
#include <stdbool.h>
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
bool isActive = true;
|
||||
bool isValid = false;
|
||||
|
||||
if (isActive) {
|
||||
printf("Active!\n");
|
||||
}
|
||||
|
||||
// Boolean operations
|
||||
bool result = isActive && !isValid; // true
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Pre-C99 approach:**
|
||||
```c
|
||||
typedef enum {
|
||||
false = 0,
|
||||
true = 1
|
||||
} bool;
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 21.11 limits.h - Implementation Limits
|
||||
|
||||
```c
|
||||
#include <limits.h>
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
printf("CHAR_BIT: %d\n", CHAR_BIT); // 8
|
||||
printf("CHAR_MIN: %d\n", CHAR_MIN);
|
||||
printf("CHAR_MAX: %d\n", CHAR_MAX);
|
||||
printf("INT_MIN: %d\n", INT_MIN); // -2147483648
|
||||
printf("INT_MAX: %d\n", INT_MAX); // 2147483647
|
||||
printf("LONG_MAX: %ld\n", LONG_MAX);
|
||||
|
||||
// Check for overflow
|
||||
int x = INT_MAX;
|
||||
if (x + 1 < x) {
|
||||
printf("Overflow detected!\n");
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 21.12 Key Concepts Learned
|
||||
- ✅ stdio.h for I/O operations
|
||||
- ✅ stdlib.h for memory and utilities
|
||||
- ✅ string.h for string manipulation
|
||||
- ✅ math.h for mathematical functions
|
||||
- ✅ ctype.h for character handling
|
||||
- ✅ time.h for time/date operations
|
||||
- ✅ assert.h for debugging
|
||||
- ✅ stdint.h for fixed-width types
|
||||
- ✅ stdbool.h for boolean type
|
||||
- ✅ Clay's zero-dependency approach
|
||||
|
||||
---
|
||||
|
||||
## Practice Exercises
|
||||
|
||||
1. Write a program to read a file and count words
|
||||
2. Implement your own strlen without using stdlib
|
||||
3. Create a simple calculator using scanf and math.h
|
||||
4. Build a random password generator
|
||||
5. Make a function to format time as "X days, Y hours, Z minutes"
|
||||
6. Implement case-insensitive string comparison
|
||||
7. Create a memory pool allocator (like Clay's arena)
|
||||
8. Write a benchmark utility using clock()
|
||||
805
docs/22_file_io.md
Normal file
805
docs/22_file_io.md
Normal file
|
|
@ -0,0 +1,805 @@
|
|||
# Chapter 22: File I/O in C
|
||||
|
||||
## Complete Guide with Clay Library Examples
|
||||
|
||||
---
|
||||
|
||||
## 22.1 Introduction to File I/O
|
||||
|
||||
C provides file operations through `stdio.h`:
|
||||
- Open files
|
||||
- Read/write data
|
||||
- Close files
|
||||
- Navigate file position
|
||||
- Check file status
|
||||
|
||||
**Clay's Approach:** Clay doesn't do file I/O - it's a UI layout library. But applications using Clay need file operations for saving/loading UI state, configurations, etc.
|
||||
|
||||
---
|
||||
|
||||
## 22.2 Opening and Closing Files
|
||||
|
||||
### Basic File Operations
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file;
|
||||
|
||||
// Open file for writing
|
||||
file = fopen("output.txt", "w");
|
||||
if (file == NULL) {
|
||||
printf("Error opening file!\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
// Write to file
|
||||
fprintf(file, "Hello, File!\n");
|
||||
|
||||
// Close file
|
||||
fclose(file);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### File Modes
|
||||
|
||||
| Mode | Description | Creates if not exists | Truncates existing |
|
||||
|------|-------------|----------------------|-------------------|
|
||||
| `"r"` | Read only | No | No |
|
||||
| `"w"` | Write only | Yes | Yes |
|
||||
| `"a"` | Append | Yes | No |
|
||||
| `"r+"` | Read/Write | No | No |
|
||||
| `"w+"` | Read/Write | Yes | Yes |
|
||||
| `"a+"` | Read/Append | Yes | No |
|
||||
| `"rb"` | Read binary | No | No |
|
||||
| `"wb"` | Write binary | Yes | Yes |
|
||||
|
||||
```c
|
||||
FILE *fr = fopen("input.txt", "r"); // Read text
|
||||
FILE *fw = fopen("output.txt", "w"); // Write text
|
||||
FILE *fa = fopen("log.txt", "a"); // Append text
|
||||
FILE *fb = fopen("data.bin", "rb"); // Read binary
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.3 Writing to Files
|
||||
|
||||
### fprintf - Formatted Output
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("data.txt", "w");
|
||||
if (file == NULL) {
|
||||
return 1;
|
||||
}
|
||||
|
||||
int age = 25;
|
||||
float height = 5.9f;
|
||||
char name[] = "John";
|
||||
|
||||
// Write formatted data
|
||||
fprintf(file, "Name: %s\n", name);
|
||||
fprintf(file, "Age: %d\n", age);
|
||||
fprintf(file, "Height: %.1f\n", height);
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### fputs - Write String
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("output.txt", "w");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
fputs("Line 1\n", file);
|
||||
fputs("Line 2\n", file);
|
||||
fputs("Line 3\n", file);
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### fputc - Write Character
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("output.txt", "w");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
fputc('H', file);
|
||||
fputc('i', file);
|
||||
fputc('\n', file);
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### fwrite - Write Binary Data
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
typedef struct {
|
||||
int id;
|
||||
char name[50];
|
||||
float salary;
|
||||
} Employee;
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("employees.dat", "wb");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
Employee emp = {1, "John Doe", 50000.0f};
|
||||
|
||||
// Write struct to binary file
|
||||
size_t written = fwrite(&emp, sizeof(Employee), 1, file);
|
||||
if (written != 1) {
|
||||
printf("Write error!\n");
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.4 Reading from Files
|
||||
|
||||
### fscanf - Formatted Input
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("data.txt", "r");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
char name[50];
|
||||
int age;
|
||||
float height;
|
||||
|
||||
// Read formatted data
|
||||
fscanf(file, "Name: %s\n", name);
|
||||
fscanf(file, "Age: %d\n", &age);
|
||||
fscanf(file, "Height: %f\n", &height);
|
||||
|
||||
printf("Name: %s, Age: %d, Height: %.1f\n", name, age, height);
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### fgets - Read Line
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("input.txt", "r");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
char buffer[256];
|
||||
|
||||
// Read line by line
|
||||
while (fgets(buffer, sizeof(buffer), file) != NULL) {
|
||||
printf("%s", buffer);
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### fgetc - Read Character
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("input.txt", "r");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
int ch;
|
||||
|
||||
// Read character by character
|
||||
while ((ch = fgetc(file)) != EOF) {
|
||||
putchar(ch);
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### fread - Read Binary Data
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
typedef struct {
|
||||
int id;
|
||||
char name[50];
|
||||
float salary;
|
||||
} Employee;
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("employees.dat", "rb");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
Employee emp;
|
||||
|
||||
// Read struct from binary file
|
||||
size_t read = fread(&emp, sizeof(Employee), 1, file);
|
||||
if (read == 1) {
|
||||
printf("ID: %d, Name: %s, Salary: %.2f\n",
|
||||
emp.id, emp.name, emp.salary);
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.5 File Position
|
||||
|
||||
### ftell - Get Position
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("data.txt", "r");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
// Get current position
|
||||
long pos = ftell(file);
|
||||
printf("Position: %ld\n", pos); // 0 (at start)
|
||||
|
||||
// Read some data
|
||||
char buffer[10];
|
||||
fgets(buffer, sizeof(buffer), file);
|
||||
|
||||
// Get new position
|
||||
pos = ftell(file);
|
||||
printf("Position after read: %ld\n", pos);
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### fseek - Set Position
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("data.txt", "r");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
// Seek to end
|
||||
fseek(file, 0, SEEK_END);
|
||||
long size = ftell(file);
|
||||
printf("File size: %ld bytes\n", size);
|
||||
|
||||
// Seek to beginning
|
||||
fseek(file, 0, SEEK_SET);
|
||||
|
||||
// Seek forward 10 bytes
|
||||
fseek(file, 10, SEEK_CUR);
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Seek origins:**
|
||||
- `SEEK_SET` - Beginning of file
|
||||
- `SEEK_CUR` - Current position
|
||||
- `SEEK_END` - End of file
|
||||
|
||||
### rewind - Reset to Beginning
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("data.txt", "r");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
// Read file
|
||||
char buffer[100];
|
||||
fgets(buffer, sizeof(buffer), file);
|
||||
|
||||
// Go back to start
|
||||
rewind(file); // Same as fseek(file, 0, SEEK_SET)
|
||||
|
||||
// Read again
|
||||
fgets(buffer, sizeof(buffer), file);
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.6 File Status
|
||||
|
||||
### feof - Check End of File
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("input.txt", "r");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
char ch;
|
||||
while (!feof(file)) {
|
||||
ch = fgetc(file);
|
||||
if (ch != EOF) {
|
||||
putchar(ch);
|
||||
}
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### ferror - Check Errors
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("output.txt", "w");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
fprintf(file, "Test\n");
|
||||
|
||||
if (ferror(file)) {
|
||||
printf("Error writing to file!\n");
|
||||
clearerr(file); // Clear error flag
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### File Existence
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int fileExists(const char *filename) {
|
||||
FILE *file = fopen(filename, "r");
|
||||
if (file != NULL) {
|
||||
fclose(file);
|
||||
return 1;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
if (fileExists("config.txt")) {
|
||||
printf("Config file found!\n");
|
||||
} else {
|
||||
printf("Config file not found!\n");
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.7 Practical Examples
|
||||
|
||||
### Copy File
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int copyFile(const char *src, const char *dest) {
|
||||
FILE *source = fopen(src, "rb");
|
||||
if (source == NULL) return 0;
|
||||
|
||||
FILE *target = fopen(dest, "wb");
|
||||
if (target == NULL) {
|
||||
fclose(source);
|
||||
return 0;
|
||||
}
|
||||
|
||||
// Copy buffer by buffer
|
||||
char buffer[1024];
|
||||
size_t bytes;
|
||||
|
||||
while ((bytes = fread(buffer, 1, sizeof(buffer), source)) > 0) {
|
||||
fwrite(buffer, 1, bytes, target);
|
||||
}
|
||||
|
||||
fclose(source);
|
||||
fclose(target);
|
||||
return 1;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
if (copyFile("input.txt", "output.txt")) {
|
||||
printf("File copied successfully!\n");
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Count Lines in File
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int countLines(const char *filename) {
|
||||
FILE *file = fopen(filename, "r");
|
||||
if (file == NULL) return -1;
|
||||
|
||||
int lines = 0;
|
||||
int ch;
|
||||
|
||||
while ((ch = fgetc(file)) != EOF) {
|
||||
if (ch == '\n') {
|
||||
lines++;
|
||||
}
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return lines;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
int lines = countLines("input.txt");
|
||||
printf("Lines: %d\n", lines);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
### Read Entire File
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
|
||||
char* readFile(const char *filename, size_t *size) {
|
||||
FILE *file = fopen(filename, "rb");
|
||||
if (file == NULL) return NULL;
|
||||
|
||||
// Get file size
|
||||
fseek(file, 0, SEEK_END);
|
||||
long filesize = ftell(file);
|
||||
rewind(file);
|
||||
|
||||
// Allocate buffer
|
||||
char *buffer = (char*)malloc(filesize + 1);
|
||||
if (buffer == NULL) {
|
||||
fclose(file);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
// Read entire file
|
||||
size_t read = fread(buffer, 1, filesize, file);
|
||||
buffer[read] = '\0'; // Null terminate
|
||||
|
||||
if (size != NULL) {
|
||||
*size = read;
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return buffer;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
size_t size;
|
||||
char *content = readFile("input.txt", &size);
|
||||
|
||||
if (content != NULL) {
|
||||
printf("Content (%zu bytes):\n%s\n", size, content);
|
||||
free(content);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.8 Configuration File (Clay Example)
|
||||
|
||||
### Save Clay UI Configuration
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
typedef struct {
|
||||
float width;
|
||||
float height;
|
||||
int layoutDirection;
|
||||
int padding;
|
||||
} Clay_LayoutConfig;
|
||||
|
||||
int saveLayoutConfig(const char *filename, Clay_LayoutConfig *config) {
|
||||
FILE *file = fopen(filename, "w");
|
||||
if (file == NULL) return 0;
|
||||
|
||||
fprintf(file, "width=%.2f\n", config->width);
|
||||
fprintf(file, "height=%.2f\n", config->height);
|
||||
fprintf(file, "layoutDirection=%d\n", config->layoutDirection);
|
||||
fprintf(file, "padding=%d\n", config->padding);
|
||||
|
||||
fclose(file);
|
||||
return 1;
|
||||
}
|
||||
|
||||
int loadLayoutConfig(const char *filename, Clay_LayoutConfig *config) {
|
||||
FILE *file = fopen(filename, "r");
|
||||
if (file == NULL) return 0;
|
||||
|
||||
fscanf(file, "width=%f\n", &config->width);
|
||||
fscanf(file, "height=%f\n", &config->height);
|
||||
fscanf(file, "layoutDirection=%d\n", &config->layoutDirection);
|
||||
fscanf(file, "padding=%d\n", &config->padding);
|
||||
|
||||
fclose(file);
|
||||
return 1;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
Clay_LayoutConfig config = {
|
||||
.width = 800.0f,
|
||||
.height = 600.0f,
|
||||
.layoutDirection = 0,
|
||||
.padding = 16
|
||||
};
|
||||
|
||||
// Save config
|
||||
saveLayoutConfig("layout.cfg", &config);
|
||||
|
||||
// Load config
|
||||
Clay_LayoutConfig loaded = {0};
|
||||
if (loadLayoutConfig("layout.cfg", &loaded)) {
|
||||
printf("Loaded: %.0fx%.0f, dir=%d, pad=%d\n",
|
||||
loaded.width, loaded.height,
|
||||
loaded.layoutDirection, loaded.padding);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.9 Binary File Format
|
||||
|
||||
### Save/Load Array
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
|
||||
typedef struct {
|
||||
int count;
|
||||
float *values;
|
||||
} FloatArray;
|
||||
|
||||
int saveFloatArray(const char *filename, FloatArray *arr) {
|
||||
FILE *file = fopen(filename, "wb");
|
||||
if (file == NULL) return 0;
|
||||
|
||||
// Write count
|
||||
fwrite(&arr->count, sizeof(int), 1, file);
|
||||
|
||||
// Write values
|
||||
fwrite(arr->values, sizeof(float), arr->count, file);
|
||||
|
||||
fclose(file);
|
||||
return 1;
|
||||
}
|
||||
|
||||
FloatArray* loadFloatArray(const char *filename) {
|
||||
FILE *file = fopen(filename, "rb");
|
||||
if (file == NULL) return NULL;
|
||||
|
||||
FloatArray *arr = (FloatArray*)malloc(sizeof(FloatArray));
|
||||
|
||||
// Read count
|
||||
fread(&arr->count, sizeof(int), 1, file);
|
||||
|
||||
// Allocate and read values
|
||||
arr->values = (float*)malloc(arr->count * sizeof(float));
|
||||
fread(arr->values, sizeof(float), arr->count, file);
|
||||
|
||||
fclose(file);
|
||||
return arr;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
// Create array
|
||||
FloatArray arr;
|
||||
arr.count = 5;
|
||||
arr.values = (float*)malloc(5 * sizeof(float));
|
||||
for (int i = 0; i < 5; i++) {
|
||||
arr.values[i] = i * 1.5f;
|
||||
}
|
||||
|
||||
// Save
|
||||
saveFloatArray("data.bin", &arr);
|
||||
|
||||
// Load
|
||||
FloatArray *loaded = loadFloatArray("data.bin");
|
||||
if (loaded != NULL) {
|
||||
printf("Loaded %d values:\n", loaded->count);
|
||||
for (int i = 0; i < loaded->count; i++) {
|
||||
printf("%.1f ", loaded->values[i]);
|
||||
}
|
||||
printf("\n");
|
||||
|
||||
free(loaded->values);
|
||||
free(loaded);
|
||||
}
|
||||
|
||||
free(arr.values);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.10 Error Handling
|
||||
|
||||
### Robust File Operations
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <errno.h>
|
||||
#include <string.h>
|
||||
|
||||
typedef enum {
|
||||
FILE_OK,
|
||||
FILE_ERROR_OPEN,
|
||||
FILE_ERROR_READ,
|
||||
FILE_ERROR_WRITE
|
||||
} FileError;
|
||||
|
||||
FileError writeData(const char *filename, const char *data) {
|
||||
FILE *file = fopen(filename, "w");
|
||||
if (file == NULL) {
|
||||
printf("Open error: %s\n", strerror(errno));
|
||||
return FILE_ERROR_OPEN;
|
||||
}
|
||||
|
||||
if (fputs(data, file) == EOF) {
|
||||
printf("Write error: %s\n", strerror(errno));
|
||||
fclose(file);
|
||||
return FILE_ERROR_WRITE;
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return FILE_OK;
|
||||
}
|
||||
|
||||
int main(void) {
|
||||
FileError err = writeData("output.txt", "Hello!\n");
|
||||
if (err != FILE_OK) {
|
||||
printf("Error code: %d\n", err);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.11 Temporary Files
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
// Create temporary file
|
||||
FILE *temp = tmpfile();
|
||||
if (temp == NULL) {
|
||||
printf("Error creating temp file!\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
// Use temp file
|
||||
fprintf(temp, "Temporary data\n");
|
||||
rewind(temp);
|
||||
|
||||
char buffer[100];
|
||||
fgets(buffer, sizeof(buffer), temp);
|
||||
printf("Read: %s", buffer);
|
||||
|
||||
// File automatically deleted on close
|
||||
fclose(temp);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.12 Buffer Control
|
||||
|
||||
### Set Buffer Mode
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
FILE *file = fopen("output.txt", "w");
|
||||
if (file == NULL) return 1;
|
||||
|
||||
// Disable buffering
|
||||
setbuf(file, NULL);
|
||||
|
||||
// Or set custom buffer
|
||||
char buffer[BUFSIZ];
|
||||
setvbuf(file, buffer, _IOFBF, BUFSIZ); // Full buffering
|
||||
|
||||
// _IONBF = No buffering
|
||||
// _IOLBF = Line buffering
|
||||
// _IOFBF = Full buffering
|
||||
|
||||
fprintf(file, "Data\n");
|
||||
|
||||
// Force write buffer
|
||||
fflush(file);
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 22.13 Key Concepts Learned
|
||||
- ✅ Opening and closing files
|
||||
- ✅ File modes (read, write, append, binary)
|
||||
- ✅ Writing: fprintf, fputs, fputc, fwrite
|
||||
- ✅ Reading: fscanf, fgets, fgetc, fread
|
||||
- ✅ File position: ftell, fseek, rewind
|
||||
- ✅ File status: feof, ferror
|
||||
- ✅ Binary file operations
|
||||
- ✅ Error handling
|
||||
- ✅ Configuration files
|
||||
- ✅ Buffer control
|
||||
|
||||
---
|
||||
|
||||
## Practice Exercises
|
||||
|
||||
1. Create a text editor that can save/load files
|
||||
2. Build a CSV parser and writer
|
||||
3. Implement a simple database using binary files
|
||||
4. Create a log file system with timestamps
|
||||
5. Write a file encryption/decryption program
|
||||
6. Build a file comparison utility (diff)
|
||||
7. Implement a config file parser (INI format)
|
||||
8. Create a file compression utility (run-length encoding)
|
||||
817
docs/23_command_line_arguments.md
Normal file
817
docs/23_command_line_arguments.md
Normal file
|
|
@ -0,0 +1,817 @@
|
|||
# Chapter 23: Command-Line Arguments in C
|
||||
|
||||
## Complete Guide with Clay Library Examples
|
||||
|
||||
---
|
||||
|
||||
## 23.1 Introduction to Command-Line Arguments
|
||||
|
||||
When you run a program from the terminal:
|
||||
```bash
|
||||
./program arg1 arg2 arg3
|
||||
```
|
||||
|
||||
C provides access to these arguments through `main`:
|
||||
|
||||
```c
|
||||
int main(int argc, char *argv[]) {
|
||||
// argc = argument count
|
||||
// argv = argument vector (array of strings)
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Parts:**
|
||||
- `argc` - Number of arguments (including program name)
|
||||
- `argv` - Array of argument strings
|
||||
- `argv[0]` - Program name
|
||||
- `argv[1]` to `argv[argc-1]` - Actual arguments
|
||||
- `argv[argc]` - NULL pointer
|
||||
|
||||
---
|
||||
|
||||
## 23.2 Basic Example
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
printf("Program name: %s\n", argv[0]);
|
||||
printf("Argument count: %d\n", argc);
|
||||
|
||||
printf("Arguments:\n");
|
||||
for (int i = 0; i < argc; i++) {
|
||||
printf(" argv[%d] = %s\n", i, argv[i]);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Running:**
|
||||
```bash
|
||||
$ ./program hello world 123
|
||||
Program name: ./program
|
||||
Argument count: 4
|
||||
Arguments:
|
||||
argv[0] = ./program
|
||||
argv[1] = hello
|
||||
argv[2] = world
|
||||
argv[3] = 123
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.3 Processing Arguments
|
||||
|
||||
### Check Argument Count
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
if (argc != 3) {
|
||||
printf("Usage: %s <name> <age>\n", argv[0]);
|
||||
return 1;
|
||||
}
|
||||
|
||||
char *name = argv[1];
|
||||
int age = atoi(argv[2]); // Convert string to int
|
||||
|
||||
printf("Name: %s, Age: %d\n", name, age);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Running:**
|
||||
```bash
|
||||
$ ./program John 25
|
||||
Name: John, Age: 25
|
||||
|
||||
$ ./program John
|
||||
Usage: ./program <name> <age>
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.4 Parsing Numeric Arguments
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
if (argc != 4) {
|
||||
printf("Usage: %s <a> <b> <c>\n", argv[0]);
|
||||
return 1;
|
||||
}
|
||||
|
||||
// Convert arguments to numbers
|
||||
int a = atoi(argv[1]); // Integer
|
||||
long b = atol(argv[2]); // Long
|
||||
double c = atof(argv[3]); // Double
|
||||
|
||||
printf("a = %d\n", a);
|
||||
printf("b = %ld\n", b);
|
||||
printf("c = %.2f\n", c);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Running:**
|
||||
```bash
|
||||
$ ./program 10 1000000 3.14
|
||||
a = 10
|
||||
b = 1000000
|
||||
c = 3.14
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.5 Command-Line Flags
|
||||
|
||||
### Simple Flags
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
int verbose = 0;
|
||||
int debug = 0;
|
||||
|
||||
// Check for flags
|
||||
for (int i = 1; i < argc; i++) {
|
||||
if (strcmp(argv[i], "-v") == 0 ||
|
||||
strcmp(argv[i], "--verbose") == 0) {
|
||||
verbose = 1;
|
||||
}
|
||||
else if (strcmp(argv[i], "-d") == 0 ||
|
||||
strcmp(argv[i], "--debug") == 0) {
|
||||
debug = 1;
|
||||
}
|
||||
}
|
||||
|
||||
printf("Verbose: %s\n", verbose ? "ON" : "OFF");
|
||||
printf("Debug: %s\n", debug ? "ON" : "OFF");
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Running:**
|
||||
```bash
|
||||
$ ./program -v
|
||||
Verbose: ON
|
||||
Debug: OFF
|
||||
|
||||
$ ./program -v -d
|
||||
Verbose: ON
|
||||
Debug: ON
|
||||
|
||||
$ ./program --verbose --debug
|
||||
Verbose: ON
|
||||
Debug: ON
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.6 Flags with Values
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <stdlib.h>
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
char *output = "output.txt"; // Default
|
||||
int level = 1; // Default
|
||||
|
||||
for (int i = 1; i < argc; i++) {
|
||||
if (strcmp(argv[i], "-o") == 0 && i + 1 < argc) {
|
||||
output = argv[++i]; // Next argument is the value
|
||||
}
|
||||
else if (strcmp(argv[i], "-l") == 0 && i + 1 < argc) {
|
||||
level = atoi(argv[++i]);
|
||||
}
|
||||
}
|
||||
|
||||
printf("Output: %s\n", output);
|
||||
printf("Level: %d\n", level);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Running:**
|
||||
```bash
|
||||
$ ./program -o result.txt -l 5
|
||||
Output: result.txt
|
||||
Level: 5
|
||||
|
||||
$ ./program
|
||||
Output: output.txt
|
||||
Level: 1
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.7 getopt for Option Parsing
|
||||
|
||||
POSIX provides `getopt` for standard option parsing:
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <unistd.h> // POSIX
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
int opt;
|
||||
int verbose = 0;
|
||||
char *output = NULL;
|
||||
int level = 1;
|
||||
|
||||
// Parse options
|
||||
while ((opt = getopt(argc, argv, "vo:l:")) != -1) {
|
||||
switch (opt) {
|
||||
case 'v':
|
||||
verbose = 1;
|
||||
break;
|
||||
case 'o':
|
||||
output = optarg; // Option argument
|
||||
break;
|
||||
case 'l':
|
||||
level = atoi(optarg);
|
||||
break;
|
||||
case '?':
|
||||
printf("Unknown option: %c\n", optopt);
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
// Process remaining arguments
|
||||
for (int i = optind; i < argc; i++) {
|
||||
printf("Non-option arg: %s\n", argv[i]);
|
||||
}
|
||||
|
||||
printf("Verbose: %d\n", verbose);
|
||||
printf("Output: %s\n", output ? output : "none");
|
||||
printf("Level: %d\n", level);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Running:**
|
||||
```bash
|
||||
$ ./program -v -o test.txt -l 3 file1 file2
|
||||
Non-option arg: file1
|
||||
Non-option arg: file2
|
||||
Verbose: 1
|
||||
Output: test.txt
|
||||
Level: 3
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.8 Clay Example: UI Configuration
|
||||
|
||||
Imagine a Clay-based application with command-line options:
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
|
||||
typedef struct {
|
||||
int width;
|
||||
int height;
|
||||
int fullscreen;
|
||||
char *title;
|
||||
} AppConfig;
|
||||
|
||||
void printUsage(const char *programName) {
|
||||
printf("Usage: %s [options]\n", programName);
|
||||
printf("Options:\n");
|
||||
printf(" -w <width> Window width (default: 800)\n");
|
||||
printf(" -h <height> Window height (default: 600)\n");
|
||||
printf(" -f Fullscreen mode\n");
|
||||
printf(" -t <title> Window title\n");
|
||||
printf(" --help Show this help\n");
|
||||
}
|
||||
|
||||
int parseArgs(int argc, char *argv[], AppConfig *config) {
|
||||
// Defaults
|
||||
config->width = 800;
|
||||
config->height = 600;
|
||||
config->fullscreen = 0;
|
||||
config->title = "Clay Application";
|
||||
|
||||
for (int i = 1; i < argc; i++) {
|
||||
if (strcmp(argv[i], "-w") == 0 && i + 1 < argc) {
|
||||
config->width = atoi(argv[++i]);
|
||||
}
|
||||
else if (strcmp(argv[i], "-h") == 0 && i + 1 < argc) {
|
||||
config->height = atoi(argv[++i]);
|
||||
}
|
||||
else if (strcmp(argv[i], "-f") == 0) {
|
||||
config->fullscreen = 1;
|
||||
}
|
||||
else if (strcmp(argv[i], "-t") == 0 && i + 1 < argc) {
|
||||
config->title = argv[++i];
|
||||
}
|
||||
else if (strcmp(argv[i], "--help") == 0) {
|
||||
return 0; // Show help
|
||||
}
|
||||
else {
|
||||
printf("Unknown option: %s\n", argv[i]);
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
AppConfig config;
|
||||
|
||||
if (!parseArgs(argc, argv, &config)) {
|
||||
printUsage(argv[0]);
|
||||
return 1;
|
||||
}
|
||||
|
||||
printf("Starting Clay application:\n");
|
||||
printf(" Size: %dx%d\n", config.width, config.height);
|
||||
printf(" Fullscreen: %s\n", config.fullscreen ? "Yes" : "No");
|
||||
printf(" Title: %s\n", config.title);
|
||||
|
||||
// Initialize Clay with config
|
||||
// Clay_Dimensions screenSize = {config.width, config.height};
|
||||
// Clay_Initialize(...);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Running:**
|
||||
```bash
|
||||
$ ./clay_app -w 1024 -h 768 -f -t "My UI"
|
||||
Starting Clay application:
|
||||
Size: 1024x768
|
||||
Fullscreen: Yes
|
||||
Title: My UI
|
||||
|
||||
$ ./clay_app --help
|
||||
Usage: ./clay_app [options]
|
||||
Options:
|
||||
-w <width> Window width (default: 800)
|
||||
-h <height> Window height (default: 600)
|
||||
-f Fullscreen mode
|
||||
-t <title> Window title
|
||||
--help Show this help
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.9 Subcommands (git-style)
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
|
||||
void cmd_init(int argc, char *argv[]) {
|
||||
printf("Initializing...\n");
|
||||
}
|
||||
|
||||
void cmd_add(int argc, char *argv[]) {
|
||||
if (argc < 1) {
|
||||
printf("Error: add requires a file argument\n");
|
||||
return;
|
||||
}
|
||||
printf("Adding: %s\n", argv[0]);
|
||||
}
|
||||
|
||||
void cmd_commit(int argc, char *argv[]) {
|
||||
char *message = "Default message";
|
||||
if (argc >= 2 && strcmp(argv[0], "-m") == 0) {
|
||||
message = argv[1];
|
||||
}
|
||||
printf("Committing: %s\n", message);
|
||||
}
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
if (argc < 2) {
|
||||
printf("Usage: %s <command> [args]\n", argv[0]);
|
||||
printf("Commands: init, add, commit\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
char *command = argv[1];
|
||||
int cmd_argc = argc - 2;
|
||||
char **cmd_argv = argv + 2;
|
||||
|
||||
if (strcmp(command, "init") == 0) {
|
||||
cmd_init(cmd_argc, cmd_argv);
|
||||
}
|
||||
else if (strcmp(command, "add") == 0) {
|
||||
cmd_add(cmd_argc, cmd_argv);
|
||||
}
|
||||
else if (strcmp(command, "commit") == 0) {
|
||||
cmd_commit(cmd_argc, cmd_argv);
|
||||
}
|
||||
else {
|
||||
printf("Unknown command: %s\n", command);
|
||||
return 1;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Running:**
|
||||
```bash
|
||||
$ ./mygit init
|
||||
Initializing...
|
||||
|
||||
$ ./mygit add file.txt
|
||||
Adding: file.txt
|
||||
|
||||
$ ./mygit commit -m "Initial commit"
|
||||
Committing: Initial commit
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.10 Environment Variables
|
||||
|
||||
Access environment variables alongside arguments:
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
|
||||
int main(int argc, char *argv[], char *envp[]) {
|
||||
printf("Arguments:\n");
|
||||
for (int i = 0; i < argc; i++) {
|
||||
printf(" %s\n", argv[i]);
|
||||
}
|
||||
|
||||
printf("\nEnvironment Variables:\n");
|
||||
for (int i = 0; envp[i] != NULL; i++) {
|
||||
printf(" %s\n", envp[i]);
|
||||
}
|
||||
|
||||
// Or use getenv
|
||||
char *home = getenv("HOME");
|
||||
printf("\nHOME: %s\n", home);
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.11 Argument Validation
|
||||
|
||||
### Robust Argument Parser
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
#include <limits.h>
|
||||
#include <errno.h>
|
||||
|
||||
int parseInteger(const char *str, int *out) {
|
||||
char *endptr;
|
||||
errno = 0;
|
||||
|
||||
long val = strtol(str, &endptr, 10);
|
||||
|
||||
if (errno == ERANGE || val > INT_MAX || val < INT_MIN) {
|
||||
return 0; // Out of range
|
||||
}
|
||||
|
||||
if (endptr == str || *endptr != '\0') {
|
||||
return 0; // Not a valid number
|
||||
}
|
||||
|
||||
*out = (int)val;
|
||||
return 1;
|
||||
}
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
if (argc != 2) {
|
||||
printf("Usage: %s <number>\n", argv[0]);
|
||||
return 1;
|
||||
}
|
||||
|
||||
int value;
|
||||
if (!parseInteger(argv[1], &value)) {
|
||||
printf("Error: '%s' is not a valid integer\n", argv[1]);
|
||||
return 1;
|
||||
}
|
||||
|
||||
printf("Valid integer: %d\n", value);
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.12 Configuration Priority
|
||||
|
||||
Combine defaults, config files, and command-line arguments:
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
|
||||
typedef struct {
|
||||
int port;
|
||||
char *host;
|
||||
int debug;
|
||||
} ServerConfig;
|
||||
|
||||
void setDefaults(ServerConfig *config) {
|
||||
config->port = 8080;
|
||||
config->host = "localhost";
|
||||
config->debug = 0;
|
||||
}
|
||||
|
||||
void loadConfigFile(ServerConfig *config, const char *filename) {
|
||||
FILE *file = fopen(filename, "r");
|
||||
if (file == NULL) return;
|
||||
|
||||
char line[256];
|
||||
while (fgets(line, sizeof(line), file)) {
|
||||
if (strncmp(line, "port=", 5) == 0) {
|
||||
config->port = atoi(line + 5);
|
||||
}
|
||||
else if (strncmp(line, "host=", 5) == 0) {
|
||||
config->host = strdup(line + 5);
|
||||
// Remove newline
|
||||
config->host[strcspn(config->host, "\n")] = 0;
|
||||
}
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
}
|
||||
|
||||
void parseArgs(ServerConfig *config, int argc, char *argv[]) {
|
||||
for (int i = 1; i < argc; i++) {
|
||||
if (strcmp(argv[i], "-p") == 0 && i + 1 < argc) {
|
||||
config->port = atoi(argv[++i]);
|
||||
}
|
||||
else if (strcmp(argv[i], "-h") == 0 && i + 1 < argc) {
|
||||
config->host = argv[++i];
|
||||
}
|
||||
else if (strcmp(argv[i], "-d") == 0) {
|
||||
config->debug = 1;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
ServerConfig config;
|
||||
|
||||
// Priority: defaults < config file < command line
|
||||
setDefaults(&config);
|
||||
loadConfigFile(&config, "server.cfg");
|
||||
parseArgs(&config, argc, argv);
|
||||
|
||||
printf("Server configuration:\n");
|
||||
printf(" Host: %s\n", config.host);
|
||||
printf(" Port: %d\n", config.port);
|
||||
printf(" Debug: %s\n", config.debug ? "ON" : "OFF");
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.13 Wildcard Arguments
|
||||
|
||||
Handle wildcards expanded by shell:
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
if (argc < 2) {
|
||||
printf("Usage: %s <files...>\n", argv[0]);
|
||||
return 1;
|
||||
}
|
||||
|
||||
printf("Processing %d files:\n", argc - 1);
|
||||
for (int i = 1; i < argc; i++) {
|
||||
printf(" - %s\n", argv[i]);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
**Running:**
|
||||
```bash
|
||||
$ ./program *.txt
|
||||
Processing 3 files:
|
||||
- file1.txt
|
||||
- file2.txt
|
||||
- file3.txt
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.14 Interactive vs Batch Mode
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
|
||||
int interactiveMode(void) {
|
||||
char input[100];
|
||||
|
||||
while (1) {
|
||||
printf("> ");
|
||||
if (fgets(input, sizeof(input), stdin) == NULL) {
|
||||
break;
|
||||
}
|
||||
|
||||
// Remove newline
|
||||
input[strcspn(input, "\n")] = 0;
|
||||
|
||||
if (strcmp(input, "quit") == 0) {
|
||||
break;
|
||||
}
|
||||
|
||||
printf("You entered: %s\n", input);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int batchMode(const char *filename) {
|
||||
FILE *file = fopen(filename, "r");
|
||||
if (file == NULL) {
|
||||
printf("Error: Cannot open %s\n", filename);
|
||||
return 1;
|
||||
}
|
||||
|
||||
char line[100];
|
||||
while (fgets(line, sizeof(line), file)) {
|
||||
// Process line
|
||||
printf("Processing: %s", line);
|
||||
}
|
||||
|
||||
fclose(file);
|
||||
return 0;
|
||||
}
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
if (argc == 1) {
|
||||
// No arguments: interactive mode
|
||||
printf("Interactive mode (type 'quit' to exit)\n");
|
||||
return interactiveMode();
|
||||
}
|
||||
else {
|
||||
// Arguments provided: batch mode
|
||||
for (int i = 1; i < argc; i++) {
|
||||
printf("Processing file: %s\n", argv[i]);
|
||||
batchMode(argv[i]);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.15 Clay Application Example
|
||||
|
||||
Complete Clay application with arguments:
|
||||
|
||||
```c
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
|
||||
// #define CLAY_IMPLEMENTATION
|
||||
// #include "clay.h"
|
||||
|
||||
typedef struct {
|
||||
int width;
|
||||
int height;
|
||||
int fps;
|
||||
char *layout_file;
|
||||
int benchmark;
|
||||
} ClayAppConfig;
|
||||
|
||||
void printHelp(const char *program) {
|
||||
printf("Usage: %s [options] [layout_file]\n", program);
|
||||
printf("\nOptions:\n");
|
||||
printf(" -w, --width <N> Window width (default: 1024)\n");
|
||||
printf(" -h, --height <N> Window height (default: 768)\n");
|
||||
printf(" --fps <N> Target FPS (default: 60)\n");
|
||||
printf(" --benchmark Run in benchmark mode\n");
|
||||
printf(" --help Show this help\n");
|
||||
printf("\nExamples:\n");
|
||||
printf(" %s --width 1920 --height 1080 layout.clay\n", program);
|
||||
printf(" %s --benchmark\n", program);
|
||||
}
|
||||
|
||||
int parseArguments(int argc, char *argv[], ClayAppConfig *config) {
|
||||
// Defaults
|
||||
config->width = 1024;
|
||||
config->height = 768;
|
||||
config->fps = 60;
|
||||
config->layout_file = NULL;
|
||||
config->benchmark = 0;
|
||||
|
||||
for (int i = 1; i < argc; i++) {
|
||||
if (strcmp(argv[i], "-w") == 0 || strcmp(argv[i], "--width") == 0) {
|
||||
if (++i >= argc) return 0;
|
||||
config->width = atoi(argv[i]);
|
||||
}
|
||||
else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--height") == 0) {
|
||||
if (++i >= argc) return 0;
|
||||
config->height = atoi(argv[i]);
|
||||
}
|
||||
else if (strcmp(argv[i], "--fps") == 0) {
|
||||
if (++i >= argc) return 0;
|
||||
config->fps = atoi(argv[i]);
|
||||
}
|
||||
else if (strcmp(argv[i], "--benchmark") == 0) {
|
||||
config->benchmark = 1;
|
||||
}
|
||||
else if (strcmp(argv[i], "--help") == 0) {
|
||||
return 0;
|
||||
}
|
||||
else if (argv[i][0] != '-') {
|
||||
config->layout_file = argv[i];
|
||||
}
|
||||
else {
|
||||
printf("Unknown option: %s\n", argv[i]);
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
int main(int argc, char *argv[]) {
|
||||
ClayAppConfig config;
|
||||
|
||||
if (!parseArguments(argc, argv, &config)) {
|
||||
printHelp(argv[0]);
|
||||
return 1;
|
||||
}
|
||||
|
||||
printf("Clay Application Starting:\n");
|
||||
printf(" Resolution: %dx%d\n", config.width, config.height);
|
||||
printf(" Target FPS: %d\n", config.fps);
|
||||
printf(" Benchmark: %s\n", config.benchmark ? "Yes" : "No");
|
||||
if (config.layout_file) {
|
||||
printf(" Layout File: %s\n", config.layout_file);
|
||||
}
|
||||
|
||||
// Initialize Clay
|
||||
// Clay_Dimensions windowSize = {config.width, config.height};
|
||||
// Clay_Initialize(...);
|
||||
|
||||
// Main loop...
|
||||
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 23.16 Key Concepts Learned
|
||||
- ✅ argc and argv basics
|
||||
- ✅ Processing command-line arguments
|
||||
- ✅ Parsing numeric arguments
|
||||
- ✅ Command-line flags
|
||||
- ✅ Flags with values
|
||||
- ✅ getopt for option parsing
|
||||
- ✅ Subcommands
|
||||
- ✅ Environment variables
|
||||
- ✅ Argument validation
|
||||
- ✅ Configuration priority
|
||||
- ✅ Interactive vs batch mode
|
||||
- ✅ Clay application with arguments
|
||||
|
||||
---
|
||||
|
||||
## Practice Exercises
|
||||
|
||||
1. Build a calculator that accepts expressions as arguments
|
||||
2. Create a file search utility with filtering options
|
||||
3. Implement a CSV processor with column selection
|
||||
4. Build a simple HTTP server with configurable port
|
||||
5. Create a code formatter with style options
|
||||
6. Implement a task manager CLI (add, list, complete)
|
||||
7. Build an image converter with format options
|
||||
8. Create a benchmarking tool with various options
|
||||
455
docs/README_C_TUTORIALS.md
Normal file
455
docs/README_C_TUTORIALS.md
Normal file
|
|
@ -0,0 +1,455 @@
|
|||
# Complete C Programming Guide Using Clay Library
|
||||
|
||||
## Master C Programming Step-by-Step with Real-World Examples
|
||||
|
||||
This comprehensive guide teaches you C programming from basics to advanced concepts, using the professional Clay UI layout library as a real-world reference throughout.
|
||||
|
||||
---
|
||||
|
||||
## 📚 What You'll Learn
|
||||
|
||||
- ✅ **All C fundamentals** - Variables, operators, control flow, loops
|
||||
- ✅ **Memory management** - Pointers, arrays, dynamic allocation
|
||||
- ✅ **Advanced concepts** - Macros, bit manipulation, recursion
|
||||
- ✅ **Real-world patterns** - As demonstrated by Clay library
|
||||
- ✅ **Professional practices** - Code organization, error handling
|
||||
- ✅ **Practical applications** - File I/O, command-line tools
|
||||
|
||||
---
|
||||
|
||||
## 📖 Complete Tutorial Index
|
||||
|
||||
### Part 1: Fundamentals (Main Guide)
|
||||
**File: `LEARNING_C_WITH_CLAY.md`**
|
||||
|
||||
1. **Chapter 1: C Basics** - Your first program, includes, comments
|
||||
2. **Chapter 2: Variables and Data Types** - int, float, char, fixed-width types
|
||||
3. **Chapter 3: Operators** - Arithmetic, logical, bitwise, ternary
|
||||
4. **Chapter 4: Control Flow** - if/else, switch, goto
|
||||
5. **Chapter 5: Loops** - while, for, do-while, break, continue
|
||||
6. **Chapter 6: Functions** - Declaration, definition, parameters, recursion
|
||||
7. **Chapter 7: Pointers** - Memory addresses, dereferencing, pointer arithmetic
|
||||
8. **Chapter 8: Structs and Typedef** - Grouping data, nested structs, designated initializers
|
||||
9. **Chapter 9: Arrays** - Static arrays, multidimensional, relationship with pointers
|
||||
10. **Chapter 10: Strings** - C strings, Clay's string implementation
|
||||
11. **Chapter 11: Type Casting** - Implicit/explicit conversion, const, volatile
|
||||
12. **Chapter 12: Storage Classes** - auto, static, extern, scope, lifetime
|
||||
13. **Chapter 13: Recursion** - Base cases, tail recursion, tree traversal
|
||||
|
||||
### Part 2: Advanced Topics (Separate Files)
|
||||
|
||||
#### **Chapter 14: Bit Manipulation** 📄
|
||||
**File: `docs/14_bit_manipulation.md`**
|
||||
- Bitwise operators (&, |, ^, ~, <<, >>)
|
||||
- Bit flags and masks
|
||||
- Set/clear/toggle/check bits
|
||||
- Counting set bits
|
||||
- Power of 2 operations
|
||||
- Practical applications in Clay
|
||||
- Performance optimizations
|
||||
|
||||
#### **Chapter 15: Preprocessor and Macros**
|
||||
**File: `LEARNING_C_WITH_CLAY.md`** (Chapter 15)
|
||||
- #define and #include
|
||||
- Conditional compilation (#ifdef, #ifndef)
|
||||
- Header guards
|
||||
- Function-like macros
|
||||
- Stringification and token pasting
|
||||
- Predefined macros
|
||||
|
||||
#### **Chapter 16: Advanced Macros**
|
||||
**File: `LEARNING_C_WITH_CLAY.md`** (Chapter 16)
|
||||
- Variadic macros
|
||||
- X-Macros pattern
|
||||
- _Generic for type selection
|
||||
- Compound literals
|
||||
- For-loop macro trick (Clay's CLAY() macro)
|
||||
- Macro debugging
|
||||
|
||||
#### **Chapter 17: Memory Management**
|
||||
**File: `LEARNING_C_WITH_CLAY.md`** (Chapter 17)
|
||||
- Stack vs heap
|
||||
- malloc, calloc, realloc, free
|
||||
- Memory errors and debugging
|
||||
- Arena allocators (Clay's approach)
|
||||
- Memory pools
|
||||
- Alignment
|
||||
|
||||
#### **Chapter 18: Header Files**
|
||||
**File: `LEARNING_C_WITH_CLAY.md`** (Chapter 18)
|
||||
- Header vs source files
|
||||
- Header guards and #pragma once
|
||||
- Single-header library pattern (Clay)
|
||||
- Forward declarations
|
||||
- Opaque pointers
|
||||
- Platform-specific code
|
||||
|
||||
#### **Chapter 19: Enums and Unions**
|
||||
**File: `LEARNING_C_WITH_CLAY.md`** (Chapter 19)
|
||||
- Enum basics and typedef
|
||||
- Bit flags with enums
|
||||
- Unions for memory efficiency
|
||||
- Tagged unions
|
||||
- Anonymous structs/unions
|
||||
|
||||
#### **Chapter 20: Function Pointers**
|
||||
**File: `LEARNING_C_WITH_CLAY.md`** (Chapter 20)
|
||||
- Function pointer basics
|
||||
- Typedef for cleaner syntax
|
||||
- Callbacks (Clay's measurement callbacks)
|
||||
- Function pointer arrays
|
||||
- User data pattern
|
||||
|
||||
#### **Chapter 21: Standard Library Basics** 📄
|
||||
**File: `docs/21_standard_library.md`**
|
||||
- stdio.h - printf, scanf, file operations
|
||||
- stdlib.h - malloc, atoi, rand, exit
|
||||
- string.h - strlen, strcpy, strcmp
|
||||
- math.h - pow, sqrt, trigonometry
|
||||
- ctype.h - character testing
|
||||
- time.h - time operations
|
||||
- Clay's zero-dependency approach
|
||||
|
||||
#### **Chapter 22: File I/O** 📄
|
||||
**File: `docs/22_file_io.md`**
|
||||
- Opening and closing files
|
||||
- File modes (read, write, append, binary)
|
||||
- fprintf, fscanf, fgets, fputs
|
||||
- fread, fwrite for binary data
|
||||
- File position (ftell, fseek, rewind)
|
||||
- Error handling
|
||||
- Configuration files for Clay apps
|
||||
- Binary file formats
|
||||
|
||||
#### **Chapter 23: Command-Line Arguments** 📄
|
||||
**File: `docs/23_command_line_arguments.md`**
|
||||
- argc and argv basics
|
||||
- Parsing arguments
|
||||
- Command-line flags
|
||||
- getopt for option parsing
|
||||
- Subcommands (git-style)
|
||||
- Configuration priority
|
||||
- Clay application with arguments
|
||||
- Interactive vs batch mode
|
||||
|
||||
#### **Chapter 24: Building Complete Programs**
|
||||
**File: `LEARNING_C_WITH_CLAY.md`** (Chapter 24)
|
||||
- Complete Clay example
|
||||
- Compiling with gcc/clang
|
||||
- Makefiles for automation
|
||||
- Multi-file projects
|
||||
- Common C patterns
|
||||
- Best practices
|
||||
|
||||
---
|
||||
|
||||
## 🎯 Learning Path
|
||||
|
||||
### Beginner (Chapters 1-9)
|
||||
Start here if you're new to C. Learn the fundamentals:
|
||||
- Basic syntax and data types
|
||||
- Control structures and loops
|
||||
- Functions and pointers
|
||||
- Structs and arrays
|
||||
|
||||
**Estimated time:** 2-3 weeks
|
||||
|
||||
### Intermediate (Chapters 10-17)
|
||||
Build on fundamentals with more advanced topics:
|
||||
- String manipulation
|
||||
- Type casting and storage classes
|
||||
- Recursion and bit manipulation
|
||||
- Preprocessor and macros
|
||||
- Memory management
|
||||
|
||||
**Estimated time:** 3-4 weeks
|
||||
|
||||
### Advanced (Chapters 18-24)
|
||||
Master professional C development:
|
||||
- Project organization
|
||||
- Advanced data structures
|
||||
- Function pointers and callbacks
|
||||
- File I/O and system interaction
|
||||
- Complete application development
|
||||
|
||||
**Estimated time:** 2-3 weeks
|
||||
|
||||
---
|
||||
|
||||
## 🚀 Quick Start
|
||||
|
||||
1. **Read the main guide** (`LEARNING_C_WITH_CLAY.md`) from Chapter 1
|
||||
2. **Follow along** by writing the code examples
|
||||
3. **Study Clay's implementation** in `clay.h` for real-world patterns
|
||||
4. **Complete practice exercises** at the end of each chapter
|
||||
5. **Refer to specialized topics** in the `docs/` folder as needed
|
||||
|
||||
---
|
||||
|
||||
## 💡 Why Learn C with Clay?
|
||||
|
||||
### Clay Library Features
|
||||
- **Single-header**: Entire library in one file
|
||||
- **Zero dependencies**: No standard library required
|
||||
- **High performance**: Microsecond layout calculations
|
||||
- **Professional code**: Production-ready patterns
|
||||
- **Well-documented**: Clear, readable implementation
|
||||
|
||||
### What Clay Teaches You
|
||||
- ✅ Arena allocators for memory management
|
||||
- ✅ Macro DSL design
|
||||
- ✅ Single-header library pattern
|
||||
- ✅ API design principles
|
||||
- ✅ Zero-dependency C programming
|
||||
- ✅ Performance optimization techniques
|
||||
- ✅ Portable C code practices
|
||||
|
||||
---
|
||||
|
||||
## 📁 File Structure
|
||||
|
||||
```
|
||||
clay/
|
||||
├── LEARNING_C_WITH_CLAY.md # Main tutorial (Chapters 1-13, 15-20, 24)
|
||||
├── clay.h # The Clay library (reference)
|
||||
├── docs/
|
||||
│ ├── README_C_TUTORIALS.md # This index file
|
||||
│ ├── 14_bit_manipulation.md # Chapter 14: Bit operations
|
||||
│ ├── 21_standard_library.md # Chapter 21: stdlib overview
|
||||
│ ├── 22_file_io.md # Chapter 22: File operations
|
||||
│ └── 23_command_line_arguments.md # Chapter 23: argc/argv
|
||||
└── examples/ # Clay examples to study
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 🔧 Prerequisites
|
||||
|
||||
- A C compiler (gcc, clang, or MSVC)
|
||||
- Text editor or IDE
|
||||
- Basic command-line knowledge
|
||||
- Curiosity and patience!
|
||||
|
||||
### Setting Up
|
||||
|
||||
**Linux/Mac:**
|
||||
```bash
|
||||
gcc --version # Check compiler
|
||||
```
|
||||
|
||||
**Windows:**
|
||||
- Install MinGW or Visual Studio
|
||||
- Or use WSL (Windows Subsystem for Linux)
|
||||
|
||||
---
|
||||
|
||||
## 📝 How to Use This Guide
|
||||
|
||||
### Reading the Main Tutorial
|
||||
|
||||
```bash
|
||||
# View in terminal
|
||||
less LEARNING_C_WITH_CLAY.md
|
||||
|
||||
# Or open in your favorite markdown viewer
|
||||
```
|
||||
|
||||
### Compiling Examples
|
||||
|
||||
```c
|
||||
// example.c
|
||||
#include <stdio.h>
|
||||
|
||||
int main(void) {
|
||||
printf("Hello, C!\n");
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
```bash
|
||||
# Compile
|
||||
gcc -o example example.c
|
||||
|
||||
# Run
|
||||
./example
|
||||
```
|
||||
|
||||
### Studying Clay
|
||||
|
||||
```c
|
||||
// your_program.c
|
||||
#define CLAY_IMPLEMENTATION
|
||||
#include "clay.h"
|
||||
|
||||
int main(void) {
|
||||
// Your Clay UI code here
|
||||
return 0;
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 🎓 Practice Exercises
|
||||
|
||||
Each chapter includes practice exercises. Try them all!
|
||||
|
||||
**Example exercises:**
|
||||
- Chapter 5: Build a number guessing game
|
||||
- Chapter 7: Implement your own string functions
|
||||
- Chapter 14: Create a permission system with bit flags
|
||||
- Chapter 22: Build a CSV parser
|
||||
- Chapter 24: Create a complete Clay application
|
||||
|
||||
---
|
||||
|
||||
## 📚 Additional Resources
|
||||
|
||||
### Clay Resources
|
||||
- **Clay Website**: https://nicbarker.com/clay
|
||||
- **Clay GitHub**: https://github.com/nicbarker/clay
|
||||
- **Examples**: See `clay/examples/` directory
|
||||
|
||||
### C Programming Resources
|
||||
- **C Reference**: https://en.cppreference.com/w/c
|
||||
- **Book**: "The C Programming Language" by K&R
|
||||
- **Book**: "Modern C" by Jens Gustedt
|
||||
- **Online**: C tutorials on YouTube, freeCodeCamp
|
||||
|
||||
### Tools
|
||||
- **Compiler Explorer**: https://godbolt.org
|
||||
- **Valgrind**: Memory leak detection
|
||||
- **GDB**: Debugging
|
||||
- **Clang-format**: Code formatting
|
||||
|
||||
---
|
||||
|
||||
## 🤝 Contributing
|
||||
|
||||
Found an error? Have a suggestion? Contributions welcome!
|
||||
|
||||
---
|
||||
|
||||
## ⭐ Features of This Guide
|
||||
|
||||
- ✅ **Progressive learning** - Start simple, build complexity
|
||||
- ✅ **Real-world examples** - Every concept shown in Clay
|
||||
- ✅ **Complete coverage** - All C topics from basics to advanced
|
||||
- ✅ **Practical focus** - Build real programs, not just theory
|
||||
- ✅ **Professional patterns** - Learn industry best practices
|
||||
- ✅ **Zero to hero** - From "Hello World" to complex applications
|
||||
|
||||
---
|
||||
|
||||
## 🎯 Learning Goals
|
||||
|
||||
After completing this guide, you will be able to:
|
||||
|
||||
1. ✅ Write efficient, well-structured C programs
|
||||
2. ✅ Understand memory management and pointers
|
||||
3. ✅ Use advanced C features (macros, unions, bit manipulation)
|
||||
4. ✅ Organize multi-file C projects
|
||||
5. ✅ Read and understand professional C code (like Clay)
|
||||
6. ✅ Debug and optimize C programs
|
||||
7. ✅ Build complete applications with file I/O and CLI
|
||||
8. ✅ Apply C knowledge to systems programming
|
||||
|
||||
---
|
||||
|
||||
## 📖 Chapter Dependencies
|
||||
|
||||
```
|
||||
Chapter 1-2 (Basics)
|
||||
↓
|
||||
Chapter 3-5 (Control Flow)
|
||||
↓
|
||||
Chapter 6 (Functions)
|
||||
↓
|
||||
Chapter 7 (Pointers) ←─────────┐
|
||||
↓ │
|
||||
Chapter 8 (Structs) │
|
||||
↓ │
|
||||
Chapter 9 (Arrays) ────────────┘
|
||||
↓
|
||||
Chapter 10 (Strings)
|
||||
↓
|
||||
Chapter 11-12 (Advanced Types)
|
||||
↓
|
||||
Chapter 13 (Recursion)
|
||||
|
||||
├─→ Chapter 14 (Bit Manipulation)
|
||||
├─→ Chapter 15-16 (Macros)
|
||||
├─→ Chapter 17 (Memory)
|
||||
├─→ Chapter 18 (Organization)
|
||||
├─→ Chapter 19 (Enums/Unions)
|
||||
├─→ Chapter 20 (Function Pointers)
|
||||
├─→ Chapter 21 (Standard Library)
|
||||
├─→ Chapter 22 (File I/O)
|
||||
└─→ Chapter 23 (Command Line)
|
||||
↓
|
||||
Chapter 24 (Complete Programs)
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 🏆 Completion Checklist
|
||||
|
||||
Track your progress:
|
||||
|
||||
- [ ] Chapter 1-5: Fundamentals
|
||||
- [ ] Chapter 6-9: Functions, Pointers, Structs, Arrays
|
||||
- [ ] Chapter 10-13: Strings, Casting, Storage, Recursion
|
||||
- [ ] Chapter 14: Bit Manipulation
|
||||
- [ ] Chapter 15-16: Preprocessor and Macros
|
||||
- [ ] Chapter 17: Memory Management
|
||||
- [ ] Chapter 18: Project Organization
|
||||
- [ ] Chapter 19: Enums and Unions
|
||||
- [ ] Chapter 20: Function Pointers
|
||||
- [ ] Chapter 21: Standard Library
|
||||
- [ ] Chapter 22: File I/O
|
||||
- [ ] Chapter 23: Command-Line Arguments
|
||||
- [ ] Chapter 24: Building Complete Programs
|
||||
- [ ] Built a complete Clay application
|
||||
- [ ] Read and understood clay.h
|
||||
|
||||
---
|
||||
|
||||
## 💬 Tips for Success
|
||||
|
||||
1. **Type every example** - Don't just read, code!
|
||||
2. **Experiment** - Modify examples to see what happens
|
||||
3. **Read clay.h** - Study professional code
|
||||
4. **Complete exercises** - Practice makes perfect
|
||||
5. **Debug your errors** - Learn from mistakes
|
||||
6. **Build projects** - Apply what you learn
|
||||
7. **Ask questions** - Join C programming communities
|
||||
8. **Be patient** - C takes time to master
|
||||
|
||||
---
|
||||
|
||||
## 🚀 Next Steps After This Guide
|
||||
|
||||
1. **Build projects** - Create your own applications
|
||||
2. **Study data structures** - Implement lists, trees, hash tables
|
||||
3. **Learn algorithms** - Sorting, searching, graph algorithms
|
||||
4. **Explore systems programming** - OS concepts, networking
|
||||
5. **Contribute to open source** - Read and improve real projects
|
||||
6. **Specialize** - Embedded systems, game dev, or systems programming
|
||||
|
||||
---
|
||||
|
||||
## 📜 License
|
||||
|
||||
This educational content is provided for learning purposes.
|
||||
Clay library: MIT License - see Clay repository for details.
|
||||
|
||||
---
|
||||
|
||||
## 🎉 Happy Coding!
|
||||
|
||||
Welcome to the world of C programming! With dedication and practice, you'll master one of the most powerful and influential programming languages ever created.
|
||||
|
||||
**Remember:** Every expert was once a beginner. Start with Chapter 1 and work your way through. You've got this! 🚀
|
||||
|
||||
---
|
||||
|
||||
*"C is quirky, flawed, and an enormous success." - Dennis Ritchie*
|
||||
Loading…
Reference in a new issue