C Program to Calculate Sum of Digits of a Number Using Recursion

Recursion in C means a function calling itself. In the program below the function finds the sum of digits by recursively passing the quotient after dividing the number by 10 until the number becomes 0.

//C program to Calculate sum of digits using recursion

Description-

#include <stdio.h>
 int sum (int n);
 int main()
{
    int number, res;
 
    printf("Enter the number: ");
    scanf("%d", &number);			//taking input
    res = sum(number);			//calling the recursive function
    printf("Sum of digits in %d is %d\n", number, res);
    return 0;
}
 
int sum (int number)		//recursive function for summation
{
    if (number != 0)
    {
        return (number % 10 + sum (num/ 10));
    }
    else
    {
       return 0;
    }
}

Output