# Write a program that converts numerical values (ie. 5) into their English equivalent (five).
print "Enter a postive number: "
user_number = gets.chomp.to_i

def english_number(number)
  number_string = ''
  ones = "One Two Three Four Five Six Seven Eight Nine".split(' ')
  tens = "Twenty Thirty Fourty Fifty Sixty Seventy Eighty Ninety".split(' ')
  teens = "Eleven Twelve Thirteen Fourteen Fifteen Sixteen Seventeen Eighteen Nineteen".split(' ')

  if number < 0
    return "Please enter a positive integer."
  end

  if number == 0
    return "Zero"
  end

  if number >= 1*10E8
    # Billions
    number_string += english_number(number / (1*10E8.to_i)) + " Billion"
    number -= (number / (1*10E8.to_i)) * (1*10E8.to_i)

    number_string += " " if number > 0
  end

  if number >= 1*10E5
    # Millions
    number_string += english_number(number / (1*10E5.to_i)) + " Million"
    number -= (number / (1*10E5.to_i)) * (1*10E5.to_i)

    number_string += " " if number > 0
  end

  if number >= 1*10E2
    # Thousands
    number_string += english_number(number / (1*10E2.to_i)) + " Thousand"
    number -= (number / (1*10E2.to_i)) * (1*10E2.to_i)

    number_string += " " if number > 0
  end

  if number >= 1*10E1
    # Hundreds
    number_string += english_number(number / (1*10E1.to_i)) + " Hundred"
    number -= (number / (1*10E1.to_i)) * (1*10E1.to_i)

    number_string += " " if number > 0
  end

  if number >= 20
    # Tens
    tens_val = number/10
    number_string += tens[number/10 - 2]
    number -= tens_val * 10

    number_string += " " if number > 0
  end

  if number > 10
    # Teens
    number_string += teens[number % 10 - 1]
    number %= 10

    number_string += " " if number > 0
  end

  if number == 10
    number_string += "Ten"
  else
    number_string += ones[number - 1]
  end

  return number_string
end

puts "You entered " + english_number(user_number)