gistfile1.rb

def to_words(num)
  a0 = %w{ one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen }
  a1 = %w{ twenty thirty forty fifty sixty seventy eighty ninety }
  case num
  when 1..19
    a0[num-1]
  when 20..99
    num % 10 != 0 ? "#{a1[(num-20)/10]}#{a0[num % 10 - 1]}" : a1[(num-20)/10]
  when 100..999
    num % 100 != 0 ? "#{to_words(num/100)}hundredand#{to_words(num % 100)}" : "#{to_words(num/100)}hundred"
  when 1000
    "onethousand"
  end
end