English Numerals by @Nari3 , @Watson1978 #minatork01

en.rb

require_relative "ex_numeric"

puts ARGV.shift.to_i.to_english

ex_numeric.rb

class Numeric
  def to_english
    return NumToEnglish.new.convert(self)
  end
end

class NumToEnglish
  def initialize
    @num_to_english = []
    build_num_to_english
  end

  def convert(num)
    @num_to_english[num]
  end

  private
  def build_num_to_english
    build_0_to_19
    build_20_to_99
    build_100_to_9999
  end

  def build_0_to_19
    zero_to_nineteen = %W(zero one two three four five six
       seven eight nine ten eleven twelve thirteen
       fourteen fifteen sixteen seventeen eighteen nineteen)
    @num_to_english.concat(zero_to_nineteen)
  end

  def build_20_to_99
    twenty_to_ninety = %W(twenty thirty forty fifty sixty seventy eighty ninety)
    res = twenty_to_ninety.each_with_object([]) do |i, r|
      r << "#{i}"
      (1..9).each do |j|
        r << "#{i} #{@num_to_english[j]}"
      end
    end
    @num_to_english.concat(res)
  end

  def build_100_to_9999
    (100..9999).map{|i| [(i / 100), (i % 100)] }.each do |i, j|
      if j == 0
        if (i % 10) == 0
          @num_to_english << @num_to_english[i] + " thousand"
        else
          @num_to_english << @num_to_english[i] + " houndred"
        end
        next
      end

      if (i % 10) == 0
        @num_to_english << @num_to_english[i] + " thousand and " + @num_to_english[j]
      else
        @num_to_english << @num_to_english[i] + " houndred and " + @num_to_english[j]
      end
    end
  end
end