IntegerToWord.rb

TEENS = {
  0 => 'Ten',
  1 => 'Eleven',
  2 => 'Twelve',
  3 => 'Thirteen',
  4 => 'Fourteen',
  5 => 'Fifteen',
  6 => 'Sixteen',
  7 => 'Seventeen',
  8 => 'Eighteen',
  9 => 'Nineteen'
}

TENS = {
  2 => 'Twenty',
  3 => 'Thirty',
  4 => 'Forty',
  5 => 'Fifty',
  6 => 'Sixty',
  7 => 'Seventy',
  8 => 'Eighty',
  9 => 'Ninety'
}

ONES = {
  1 => 'One',
  2 => 'Two',
  3 => 'Three',
  4 => 'Four',
  5 => 'Five',
  6 => 'Six',
  7 => 'Seven',
  8 => 'Eight',
  9 => 'Nine',
}

def integerToWord(int)
  return unless (0..999).include?(int)
  return 'Zero' if int == 0
  digits = int.to_s.chars.map(&:to_i)
  result = []
  while digits.size > 0 
    case digits.size 
    when 3
      result << ONES[digits.shift] + ' Hundred' 
    when 2
      if digits.first == 1
        result << TEENS[digits.last]
        return result.join(' ')
      else  
        result << TENS[digits.shift]
      end  
    when 1
      result << ONES[digits.shift]
    end
  end  
  result.compact.join(' ')
end

# Also, works. Debately more clear.
def integerToWord2(int) 
  return unless (0..999).include?(int)
  return 'Zero' if int == 0
  digits = int.to_s.chars.map(&:to_i)
  result = [] 
  if digits.size == 3
    result << ONES[digits.shift] + ' Hundred' 
  end
  if digits.size == 2 && digits.first == 1
    result << TEENS[digits.last]
    return result.join(' ')
  end
  if digits.size == 2
    result << TENS[digits.shift]
  end  
  if digits.size == 1
    result << ONES[digits.shift] 
  end
  result.compact.join(' ')  
end  

def test(i)
  puts "#{i}: #{integerToWord(i)}"
end  


(0..999).each do |i|
  test(i)
end