Numbers in Words

number_in_words.rb

def in_words(n)
  @ones = {1 => "one", 2 => "two", 3 => "three", 4 => "four", 5 => "five", 6 => "six",
          7 => "seven", 8 => "eight", 9 => "nine", 10 => "ten", 11 => "eleven",
          12 => "twelve", 13 => "thirteen", 14 => "fourteen", 15 => "fifteen",
          16 => "sixteen", 17 => "seventeen", 18 => "eighteen", 19 => "nineteen"
          }
  @twos = {2 => "twenty", 3 => "thirty", 4 => "forty", 5 => "fifty", 6 => "sixty",
          7 => "seventy", 8 => "eighty", 9 => "ninety"
          }
  @scale = {1 => "thousand", 2 => "million", 3 => "billion", 4 => "trillion", 5 => "quadrillion",
            6 => "quintillion", 7 => "sextillion", 8 => "septillion", 9 => "octillion",
            10 => "nonillion", 11 => "decillion", 12 => "undecillion"}

  @counter = 0
  @word = String.new
  n_string = n.to_s
  
  n_string == "0" ? @word = "zero" :

  until n_string.length < 3
    set_of_threes = n_string[-3,3]
    set_of_threes = set_of_threes.to_i
    hundreds_place = set_of_threes / 100
    hundreds_rem = set_of_threes % 100
    tens_rem = set_of_threes % 1000
    if hundreds_rem < 20 && tens_rem > 0
      @word = @word.insert(0,"#{@ones[hundreds_rem]} #{@scale[@counter]} ")
    elsif hundreds_place > 0
      tens_place = hundreds_rem / 10
      tens_rem = hundreds_rem % 10
      @word = @word.insert(0,"#{@twos[tens_place]} #{@ones[tens_rem]} #{@scale[@counter]} ")
    end
    if hundreds_place > 0
      @word = @word.insert(0,"#{@ones[hundreds_place]} hundred ")
    end
    n_string.slice!(-3,3)
    @counter += 1
  end
  if n_string != ""
    leftover_digits = n_string.to_i
    if leftover_digits < 20
      @word = @word.insert(0, "#{@ones[leftover_digits]} #{@scale[@counter]} ")
    else
      tens_place = leftover_digits / 10
      tens_rem = leftover_digits % 10
      @word = @word.insert(0,"#{@twos[tens_place]} #{@ones[tens_rem]} #{@scale[@counter]} ")
    end
  end
  @word
end

puts in_words(123_456_789_123_456)

### recursive version

@ones = {1 => "one", 2 => "two", 3 => "three", 4 => "four", 5 => "five", 6 => "six",
        7 => "seven", 8 => "eight", 9 => "nine", 10 => "ten", 11 => "eleven",
        12 => "twelve", 13 => "thirteen", 14 => "fourteen", 15 => "fifteen",
        16 => "sixteen", 17 => "seventeen", 18 => "eighteen", 19 => "nineteen"
        }
        
@twos = {2 => "twenty", 3 => "thirty", 4 => "forty", 5 => "fifty", 6 => "sixty",
        7 => "seventy", 8 => "eighty", 9 => "ninety"
        }
        
@scale = {1 => "thousand", 2 => "million", 3 => "billion", 4 => "trillion", 5 => "quadrillion",
          6 => "quintillion", 7 => "sextillion", 8 => "septillion", 9 => "octillion",
          10 => "nonillion", 11 => "decillion", 12 => "undecillion"}

@counter = 0
@word = String.new

def in_words_recursive(n)
  n_string = n.to_s
  
  if n_string.length < 3
    if n_string != ""
      leftover_digits = n_string.to_i
      if leftover_digits < 20 && leftover_digits > 0
        @word = @word.insert(0, "#{@ones[leftover_digits]} #{@scale[@counter]} ")
      elsif leftover_digits >= 20
        tens_place = leftover_digits / 10
        tens_rem = leftover_digits % 10
        @word = @word.insert(0,"#{@twos[tens_place]} #{@ones[tens_rem]} #{@scale[@counter]} ")
      end
    end
    return @word
  end
    
  set_of_threes = n_string[-3,3]
  set_of_threes = set_of_threes.to_i
  hundreds_place = set_of_threes / 100
  hundreds_rem = set_of_threes % 100
  tens_rem = set_of_threes % 1000
  if hundreds_rem < 20 && tens_rem > 0
    @word = @word.insert(0,"#{@ones[hundreds_rem]} #{@scale[@counter]} ")
  elsif tens_rem > 0
    tens_place = hundreds_rem / 10
    tens_rem = hundreds_rem % 10
    @word = @word.insert(0,"#{@twos[tens_place]} #{@ones[tens_rem]} #{@scale[@counter]} ")
  end
  if hundreds_place > 0
    @word = @word.insert(0,"#{@ones[hundreds_place]} hundred ")
  end
  
  n_string.slice!(-3,3)
  n = n_string.to_i
  @counter += 1
  in_words_recursive(n)
end

puts in_words_recursive(108_229_815_000_731_090_101_002_981_456_004)