C program to add digits of a number using modulus operator(%) to extract individual digits of number and adding them.

#include <stdio.h>
 
int main()
{
   int n, sum = 0, remainder;
 
   printf("Enter an integer :");
   scanf("%d",&n);
 
   while(n != 0)
   {
      remainder = n % 10;
      sum = sum + remainder;
      n = n / 10;
   }
 
   printf("\nSum of digits of entered number = %d\n",sum);
 
   return 0;
}

/*

Output: 

Enter an integer : 12345
Sum of digits of entered number = 15
*/