Thread: need help debugging a program counting bits set from an integer number

The program is supposed to count the number of bits set by an integer. for example: 5 is 00000101 and has two bits set. compiling the program with debug statements makes me think that the program isn't even entering the integer into the loop

Code:

/********************************************************
 *							*
 * FILE: ch10_ex4.c					*
 * CREATED: 8/15/07					*
 * BY: bpf						*
 *							*
 *  this program counts the number of bits set in an 	*
 *   integer						*
 *							*
 ********************************************************/

#include<stdio.h>

main()
{
  char line[100];
  int itgr; /* the integer value of the input number */

  int r; /* remainder */
  int set = 0; /* number of variables set */
  int n; /* index into the line of bits */
  int subt = 0; /* the value to subtract from the remainder starts at zero each loop */

  /* input number */
  (void)printf("enter an integer: ");
  (void)fgets(line, sizeof(line), stdin);
  (void)sscanf(line, "%d", &itgr);

  r = itgr; /* remainder starts off the same as the integer */

  while(0)
    {      
      /* if the remainder is equal to one, the one's column is set and the loop can stop */
      if (r == 1)
	{
	  set++;

	  break;
	}

      /* if the remainder is equal to zero the number of bits set are counted and the loop stops */
      else{ if (r == 0)
	  {
	    break;
	  }

	/* the highest multiple of two is counted up to and becomes the number subtracted from the remainder */      
	else{ for (n = 1; n <= r; n * 2)
	    {
	      subt = n;
	    }

	  /* the remainder is lowered and one column is set */	  
	  r = r - subt;
	  set++;
	}
      }
    }

  /* how many bits are set */
  (void)printf("%d bits are set\n", set);

  return(0);
}