Example: C Program to Find Sum of Natural Numbers using Recursion

C
C++
C#
Java
Python
PHP

// C Program to Find Sum of Natural Numbers using Recursion
#include <stdio.h>
int recSum(int x);

// It's the driver function
int main() {
    int x; // To store a positive number

    printf("-----Enter a positive number to get the sum-----\n");
    scanf("%d", &x);

    printf("\nThe Sum is: %d\n", recSum(x));
    return 0;
}

// This function will calculate the sum of natural numbers
int recSum(int n) {
    if (n)
        return n + recSum(n - 1);
    else
        return n;
}