#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);  // say(n) will correctly say any int

void say0to99(int n)
{ if (n < 20)
    print(smalls[n]);
  else if (n < 100)
  { print(tens[n/10]);
    if (n % 10 != 0)
    { print("-");
      print(smalls[n%10]); } } }

void say100to999(int n)
{ const int hundreds = n / 100,
            remainder = n % 100;
  say(hundreds);
  print(" hundred ");
  if (remainder != 0)
  { print("and ");
    say(remainder); } }

void say1000to999999(int n)
{ const int thousands = n / 1000,
            remainder = n % 1000;
  say(thousands);
  print(" thousand ");
  if (remainder != 0)
    say(remainder); }

void say1000000to999999999(int n)
{ const int millions = n / 1000000,
            remainder = n % 1000000;
  say(millions);
  print(" million ");
  if (remainder != 0)
    say(remainder); }

void saybillions(int n)
{ const int billions = n / 1000000000,
            remainder = n % 1000000000;
  say(billions);
  print(" billion ");
  if (remainder != 0)
    say(remainder); }

void say(int n)
{ if (n < 0)
  { print("minus ");
    say(- n); }
  else if (n < 100)
    say0to99(n);
  else if (n < 1000)
    say100to999(n);
  else if (n < 1000000)
    say1000to999999(n);
  else if (n < 1000000000)
    say1000000to999999999(n);
  else
    saybillions(n); }

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

void main()
{ many_tests(); }