The following C program, using recursion, finds the sum of its digits.
Here is the source code of the C program to find an element in a linked list. The C Program is successfully compiled and run on a Linux system. The program output is also shown below.

/*
* C Program to find Sum of Digits of a Number using Recursion
*/
#include <stdio.h>

int sum (int a);

int main()
{
int num, result;

printf("Enter the number: ");
scanf("%d", &num);
result = sum(num);
printf("Sum of digits in %d is %d\n", num, result);
return 0;
}

int sum (int num)
{
if (num != 0)
{
return (num % 10 + sum (num / 10));
}
else
{
return 0;
}
}

$ cc pgm25.c
$ a.out
Enter the number: 2345
Sum of digits in 2345 is 14