Add digits of number in c

Add digits of number in c

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

Add digits using recursion 

#include <stdio.h>
 
int add_digits(int);
 
int main() 
{
  int n, result;
 
  scanf("%d", &n);
 
  result = add_digits(n);
 
  printf("%d\n", result);
 
  return 0;
}
 
int add_digits(int n) {
  static int sum = 0;
 
  if (n == 0) {
    return 0;
  }
 
  sum = n%10 + add_digits(n/10);
 
  return sum;
}