Roman Numerals with driver code, both Iterative and Recursive.

Roman_Numerals_It_Re.rb

NUM_HASH = {
  1000 => "M",
  500 => "D",
  100 => "C",
  50 => "L",
  10 => "X",
  9 => "IX",
  5 => "V",
  4 => "IV",
  1 => "I"
}

def arabic_to_roman(num, string = '')
  unless num == 0
    NUM_HASH.each do |arabic, roman|
      if num >= arabic
        until num < arabic
          string += roman
          num -= arabic

          ### for solving recursively:
          arabic_to_roman(num, string)
          
          ### for solving iteratively:
          # if num == 0 
          #   return string
          # end
        end
      end
    end
  end
  string
end

puts arabic_to_roman(2002)
puts arabic_to_roman(1000)
puts arabic_to_roman(734)
puts arabic_to_roman(205)
puts arabic_to_roman(51)
puts arabic_to_roman(9)
puts arabic_to_roman(2)