Example: Sum of Digits of a Number in C using Recursion

C
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// Sum of Digits of a Number in C using Recursion
#include <stdio.h>

// Recursive function to make the sum of each digit
int rec_sum_digits(int num, int sum, int mod)
{
    mod = num % 10;
    sum += mod;
    num = num / 10;
    if (num > 0)
        rec_sum_digits(num, sum, mod);
    else
        return sum;
}

// It's the main function of the program
int main()
{
    int num, sum = 0, mod = 0;

    // Step-1 Enter a Number
    printf("Enter Number: ");
    scanf("%d", &num);

    // Step-2 Call the recursive function rec_sum_digits() to get the sum of each digits
    printf("\nOutput: %d", rec_sum_digits(num, sum, mod));
    return 0;
}