C Examples

Practical examples of C programming concepts.

1. Hello World

#include <stdio.h>

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

2. Calculator

#include <stdio.h>

int main() {
    double num1, num2;
    char op;
    
    printf("Enter expression (e.g., 5 + 3): ");
    scanf("%lf %c %lf", &num1, &op, &num2);
    
    switch(op) {
        case '+': printf("%.2lf\n", num1 + num2); break;
        case '-': printf("%.2lf\n", num1 - num2); break;
        case '*': printf("%.2lf\n", num1 * num2); break;
        case '/': 
            if(num2 != 0) printf("%.2lf\n", num1 / num2);
            else printf("Division by zero!\n");
            break;
        default: printf("Invalid operator!\n");
    }
    
    return 0;
}

3. Array Operations

#include <stdio.h>

#define SIZE 5

int main() {
    int arr[SIZE] = {5, 2, 8, 1, 9};
    int sum = 0, max = arr[0], min = arr[0];
    
    for(int i = 0; i < SIZE; i++) {
        sum += arr[i];
        if(arr[i] > max) max = arr[i];
        if(arr[i] < min) min = arr[i];
    }
    
    printf("Sum: %d, Max: %d, Min: %d, Avg: %.2f\n", 
           sum, max, min, (float)sum/SIZE);
    
    return 0;
}

4. String Manipulation

#include <stdio.h>
#include <string.h>

int main() {
    char str1[100], str2[100];
    
    printf("Enter first string: ");
    fgets(str1, sizeof(str1), stdin);
    str1[strcspn(str1, "\n")] = '\0';  // remove newline
    
    printf("Enter second string: ");
    fgets(str2, sizeof(str2), stdin);
    str2[strcspn(str2, "\n")] = '\0';
    
    printf("Concatenated: %s %s\n", str1, str2);
    printf("Length 1: %zu, Length 2: %zu\n", strlen(str1), strlen(str2));
    
    return 0;
}