/*
  File: digitsum.c
  ----------------
  This program sums the number of digits in
  a positive integer.  The program depends on 
  the fact that the last digit of a integer n 
  is given by n % 10 and the number consisting 
  of all but the last digit is given by the
  expression n / 10.
 */

#include <stdio.h>
#include "genlib.h"
#include "simpio.h"

main()
{
    int n, dsum;

    printf("Sum the digits in an integer.\n");
    printf("Enter a positive integer: ");
    n = GetInteger();
    dsum = 0;
    while (n > 0) {
        dsum += n % 10;
        n /= 10;
    }
    printf("The sum of the digits is %d\n", dsum);
}