Thread: A Little Help Regarding Digital Root

I found an interesting problem regarding the 'digital root' of a number. In it you add the digits of a number until you find a single digit. For example, digital root of 1032 would be 1+0+3+2=6 and digital root of 2354 would be 2+3+5+4=14=1+4=5.

I made a recersive code about it but I can't arrive at a single digit. It gives you the sum of all the digits of the number but not the sum till a single digit. Here's the code:

Code:

#include<stdio.h>
int rem=0;
int digit_adder(int in)
{
	int newnum;
    rem = rem+(in%10);
    newnum=in/10;

    if(newnum==0)
    {
        return rem;
    }
    else
		return digit_adder(newnum);
}
int main()
{
    int no;
	printf ("Enter the number: \n");
	scanf ("%d", &no);
    int ans=0;
    printf("\n%d\n\n",(ans = digit_adder(no)));
	return 0;
}

How can I change it into a code that gives me the root till a single digit?

Thanks.

Code:

#include<stdio.h>
int rem=0;
int digit_adder(int in)
{
  int newnum;
  rem = rem+(in%10);
  newnum=in/10;

  if(newnum==0)
    {
      if (rem > 9) { // Added
        newnum = rem; // Added
        rem = 0; // Added
        digit_adder(newnum); // Added
      } // Added
      return rem;
    }
  else
    return digit_adder(newnum);
}
int main()
{
  int no;
  printf ("Enter the number: \n");
  scanf ("%d", &no);
  int ans=0;
  printf("\n%d\n\n",(ans = digit_adder(no)));
  return 0;
}