C Cheat Sheet

Here’s a C cheat sheet:

Hello World

#include <stdio.h>

int main() {
    printf("Hello, C!\n");
    return 0;
}

Variables and Data Types

int myInt = 42;
float myFloat = 3.14;
char myChar = 'A';
double myDouble = 2.71828;

Input/Output

#include <stdio.h>

int main() {
    int userInput;
    printf("Enter a number: ");
    scanf("%d", &userInput);
    printf("You entered: %d\n", userInput);
    return 0;
}

Control Flow

if (condition) {
    // Code to execute
} else if (anotherCondition) {
    // Code to execute if the first condition is false and this one is true
} else {
    // Code to execute if all conditions are false
}

for (int i = 0; i < 5; ++i) {
    // Code to repeat
}

Functions

#include <stdio.h>

int add(int a, int b) {
    return a + b;
}

int main() {
    int result = add(3, 4);
    printf("Result: %d\n", result);
    return 0;
}

Arrays

int myArray[5] = {1, 2, 3, 4, 5};

Pointers

int myValue = 42;
int *pointerToValue = &myValue;

Structures

struct Point {
    int x;
    int y;
};

struct Point p1 = {1, 2};

File I/O

#include <stdio.h>

int main() {
    FILE *file = fopen("example.txt", "w");
    fprintf(file, "Hello, File!");
    fclose(file);
    return 0;
}

Memory Allocation

#include <stdlib.h>

int *dynamicArray = (int *)malloc(5 * sizeof(int));
free(dynamicArray);

Command Line Arguments

#include <stdio.h>

int main(int argc, char *argv[]) {
    printf("Number of arguments: %d\n", argc);
    for (int i = 0; i < argc; ++i) {
        printf("Argument %d: %s\n", i, argv[i]);
    }
    return 0;
}

Preprocessor Directives

#define PI 3.14159

This C cheat sheet covers basic syntax, variables, control flow, functions, arrays, pointers, structures, file I/O, memory allocation, command line arguments, preprocessor directives, and provides additional resources for learning C. Adjust as needed for your specific C programming requirements.