C Programming

#include <stdio.h>

// Object-like macros
#define PI 3.14159
#define MAX_SIZE 100
#define GREETING "Hello, World!"

// Function-like macros
#define SQUARE(x) ((x) * (x))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define PRINT_VAR(var) printf(#var " = %d\n", var)

int main() {
    int radius = 5;
    float area = PI * SQUARE(radius);
    
    printf("Area of circle: %.2f\n", area);
    printf("Maximum of 10 and 20: %d\n", MAX(10, 20));
    
    int number = 42;
    PRINT_VAR(number);  // Prints: number = 42
    
    return 0;
}

#include <stdio.h>

#define DEBUG 1
#define VERSION 2

int main() {
    printf("Program started\n");
    
    #ifdef DEBUG
        printf("Debug mode is ON\n");
    #endif
    
    #ifndef RELEASE
        printf("This is not a release build\n");
    #endif
    
    #if VERSION == 1
        printf("Version 1.0\n");
    #elif VERSION == 2
        printf("Version 2.0\n");
    #else
        printf("Unknown version\n");
    #endif
    
    #if defined(DEBUG) && DEBUG > 0
        printf("Advanced debugging enabled\n");
    #endif
    
    return 0;
}

#include <stdio.h>

int main() {
    printf("File: %s\n", __FILE__);
    printf("Line: %d\n", __LINE__);
    printf("Date: %s\n", __DATE__);
    printf("Time: %s\n", __TIME__);
    printf("Function: %s\n", __func__);
    
    #ifdef __STDC__
        printf("Standard C compiler\n");
    #endif
    
    #ifdef __STDC_VERSION__
        printf("C Standard version: %ld\n", __STDC_VERSION__);
    #endif
    
    return 0;
}

#include <stdio.h>

// Stringification operator (#)
#define STRINGIFY(x) #x
#define PRINT_EXPR(expr) printf(#expr " = %d\n", expr)

// Token pasting operator (##)
#define CONCAT(a, b) a##b
#define DECLARE_VAR(type, name) type var_##name

int main() {
    // Stringification
    printf("Stringified: %s\n", STRINGIFY(Hello World));
    
    int x = 10, y = 20;
    PRINT_EXPR(x + y);  // Prints: x + y = 30
    
    // Token pasting
    int CONCAT(num, 1) = 100;  // Creates variable num1
    int CONCAT(num, 2) = 200;  // Creates variable num2
    
    printf("num1 = %d, num2 = %d\n", num1, num2);
    
    // Declare variables using macro
    DECLARE_VAR(int, count);    // Creates int var_count
    DECLARE_VAR(float, price);  // Creates float var_price
    
    var_count = 5;
    var_price = 19.99;
    
    printf("Count: %d, Price: %.2f\n", var_count, var_price);
    
    return 0;
}