text: /*  itoa: convert n to characters in s */
  void itoa(int n, char s[])
  {
      int i, sign;
  
      if ((sign = n) < 0)     // record sign
          n = -n;             // make n positive
      i = 0;
      do {                        // generate digits in reverse order
          s[i++] = n % 10 + '0';  // get next digit
      } while ((n /= 10) > 0);    // delete it
      if (sign < 0)
          s[i++] = '-';
      s[i] = '\0';
      reverse(s);
  }
  
  