Write a C program to calculate sum of digits till it reduces to a single digit using recursion.



#include<stdio.h>
#include<conio.h>
int recsum(int n);
void main()
{
  int n,ans;
  clrscr();
  printf("\n enter the number");
  scanf("\n %d",&n);
  ans= recsum(n);
 /* if(ans>9)
  {
   n=ans;
   ans=0;
   }
   */
   printf("\n sum is%d",ans);
   getch();
   }
   int recsum(int n1)
   {
             int rem,sum=0;
             if(n1==0)
               {
                          return 0;
                          }
                        else
                        {
                          rem=n1%10;
                          sum=rem+recsum(n1/10);

                         }
                          if(sum>9)
                          {
                           n1=sum;
                           sum=recsum(n1);
                           }
                          return sum;
                          }
/* output

 enter the number567
 sum is9  */