int itoa( s, n )
  char s[]; int  n;
{
  int i, j;
  int sign;
  char c;

  if ((sign = n) < 0) n = -n;
  i = 0;
  do { s[i++] = n % 10 + '0'; } while ((n /= 10) > 0);
  if (sign < 0) s[i++] = '-';
  s[i] = '\0';
  sign = i;
  for (j = i - 1, i = 0; i < j; i++, j--) {
    c = s[i];
    s[i] = s[j];
    s[j] = c;
  }
}