Functions and Recursion Examples

Demonstrates basic function declaration, definition, and calling.

#include <stdio.h>

// Function declaration
int add(int a, int b);

int main() {
    int num1, num2, result;
    
    printf("Enter two numbers: ");
    scanf("%d %d", &num1, &num2);
    
    result = add(num1, num2);
    printf("Sum: %d\n", result);
    
    return 0;
}

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

Shows recursive function implementation for calculating factorial.

#include <stdio.h>

// Recursive function to calculate factorial
long long factorial(int n) {
    if (n <= 1) {
        return 1;  // Base case
    }
    return n * factorial(n - 1);  // Recursive case
}

int main() {
    int num;
    
    printf("Enter a positive integer: ");
    scanf("%d", &num);
    
    if (num < 0) {
        printf("Factorial of negative number doesn't exist.\n");
    } else {
        printf("Factorial of %d = %lld\n", num, factorial(num));
    }
    
    return 0;
}

Demonstrates function with multiple parameters.

#include <stdio.h>

// Function to find maximum of three numbers
int findMax(int a, int b, int c) {
    int max = a;
    if (b > max) max = b;
    if (c > max) max = c;
    return max;
}

int main() {
    int x, y, z;
    
    printf("Enter three numbers: ");
    scanf("%d %d %d", &x, &y, &z);
    
    int maximum = findMax(x, y, z);
    printf("Maximum: %d\n", maximum);
    
    return 0;
}