C Program to Find Sum of Digits of a Number using Recursion

Write a C program to find sum of digits of a number using recursion.

• The function sum_of_digits() recursionly calculates the sum of digits of an integer.
• Base case: if n is 0, it returns 0 (termination condition).
• Recursion case: it adds the last digit n % 10 to the result of the recursion call with n / 10.
• The main function passes the number 1234 and prints the total sum returned by the recursion function.

#include <stdio.h>

int sum_of_digits(int n) {
    // Base case
    if (n == 0)
        return 0;
    // Recursion case
    return (n % 10) + sum_of_digits(n / 10);
}

int main() {
    int number = 1234;

    printf("Sum of digits of %d is %d\n", number, sum_of_digits(number));

    return 0;
}