#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_number(const int N)
{ 
  if (N < 0)
  { print("minus ");
    say_number(- N); }

  else if (N < 20)
    print(smalls[N]);

  else if (N < 100)
  { print(tens[N / 10]);
    if (N % 10 != 0)
    { print(" ");
      say_number(N % 10); } }

  else if (N < 1000)
  { say_number(N / 100);
    print(" hundred");
    if (N % 100 != 0)
    { print(" and ");
      say_number(N % 100); } }

  else if (N < 1000000)
  { say_number(N / 1000);
    print(" thousand");
    if (N % 1000 != 0)
    { print(" ");
      if (N % 1000 < 100)
        print("and ");
      say_number(N % 1000); } }

  else if (N < 1000000000)
  { say_number(N / 1000000);
    print(" million");
    if (N % 1000000 != 0)
    { print(" ");
      if (N % 1000000 < 100)
        print("and ");
      say_number(N % 1000000); } }

  else
  { say_number(N / 1000000000);
    print(" billion");
    if (N % 1000000000 != 0)
    { print(" ");
      if (N % 1000000000 < 100)
        print("and ");
      say_number(N % 1000000000); } } }

void test_it()
{ print("Number? ");
  const int num = read_int();
  say_number(num);
  new_line();
  test_it(); }

void main()
{ test_it(); }