/* converts the integer n into a base b representation */

#define abs(x) ((x) > 0 ? (x) : -(x))

void itob(int n, char *s, int b) {
     char charset[] = { '0', '1', '2', '3', '4', '5', '6', '7',
			'8', '9', 'A', 'B', 'C', 'D', 'E', 'F' }
     int maxbase = (sizeof charset) / sizeof (char);
     int sign;

     if (b > maxbase) {
	  *s = '\0';
	  return;
     }
     sign = n;
     do {
	  *s++ = charset[abs(n % b)];
     } while ((n /= b) > 0);
     if (n < 0)
	  *s++ = '-';
     *s = '\0';
     reverse(s);
}