Thread: how to sum the digits of a number?

sorry
679->4

i tried to do the double loop thing.
its not working

Code:

printf(" enter number  ");

scanf("%d", &digit);
copy = digit;
do
{
    sumb=0;
   do
    {
      sumb = sumb + copy % 10;

      copy = copy / 10;

       if (sumb < 10)
          {
           flag = 1;
          }


    } while (copy != 0);
    copy=sumb;
} while(flag != 1);
printf("%d",sumb);

To make it work, you would have to pay a tiny little bit of attention to what's going on. I would have thought that all that bold I used before would have pointed out your errors with flag (one, that it gets set in inappropriate places, and two, that it never gets unset once it becomes set). Fortunately there's no earthly reason to use this flag, so getting rid of it won't hurt a bit. (Notice that if you finish the loop, and at that point and at that point only sumb is less than 10, then you can stop.)

i fixed it
thanks

Code:

printf(" enter number  ");
scanf("%d", &digit);
while(digit > 10) {
    do
    {
        sumb += digit % 10;
        digit = digit / 10;
    }while(digit / 10 >1);
    digit = sumb;
}
printf("%d", 23);