#include <library.h>

const string smalls[] =
  { "zero", "one", "two", "three", "four", "five", "six", "seven",
    "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", 
    "fifteen", "sixteen", "seventeen", "eighteen", "nineteen" };

const string tens[] =
  { "zero", "ten", "twenty", "thirty", "forty", "fifty", "sixty",
    "seventy", "eighty", "ninety" };

void say(int n)
// This function works perfectly for all positive ints
{ if (n < 20)
    print(smalls[n]);
  else if (n < 100)
  { print(tens[n/10]);
    if (n % 10 != 0)
    { print("-");
      print(smalls[n%10]); } }
  else if (n < 1000)
  { const int hundreds = n / 100,
              remainder = n % 100;
    say(hundreds);
    print(" hundred ");
    if (remainder != 0)
    { print("and ");
      say(remainder); } }
  else if (n < 1000000)
  { const int thousands = n / 1000,
              remainder = n % 1000;
    say(thousands);
    print(" thousand ");
    if (remainder != 0)
      say(remainder); }
  else if (n < 1000000000)
  { const int millions = n / 1000000,
              remainder = n % 1000000;
    say(millions);
    print(" million ");
    if (remainder != 0)
      say(remainder); }
  else
  { const int billions = n / 1000000000,
              remainder = n % 1000000000;
    say(billions);
    print(" billion ");
    if (remainder != 0)
      say(remainder); } }

void many_tests()
{ print("enter an int: ");
  const int n = read_int();
  say(n);
  new_line();
  many_tests(); }

void main()
{ many_tests(); }