C Program to Find the Sum of Natural Numbers using Recursion

Posted by Annie Sanjana

This post helps us to find the sum of natural numbers using recursion using C programming.

C Program to Find the Sum of Natural Numbers using Recursion

#include<stdio.h>
int recusum(int s);
int main()
{
    int num;
    printf("Enter a positive number:");
    scanf("%d",&num);
    printf("sum=%d",recusum(num));
    return 0;
}
//function calling process
int recusum(int s)
{
    if(s!=0)
        return s+recusum(s-1);
    else
        return s;
}

Output

Explanation

This C program uses the recursion function, its the process of repeating items in a self-similar way, in simple words function calls itself. In this program, we initialize a function namely recusum(int s), and in the main function, we iterate a variable named num.

int recusum(int s);
int main()
{
    int num;
    printf("Enter a positive number:");
    scanf("%d",&num);
    printf("sum=%d",recusum(num));
    return 0;
}

The function is called for the calculation and to get the desired result. Using the if-else condition we calculate the recursion value of the number entered by the user.

//function calling process
int recusum(int s)
{
    if(s!=0)
        return s+recusum(s-1);
    else
        return s;
}

After the calculation part. we have now obtained the desired output.

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