"RPN Calculator"

gistfile1.txt

class RPNCalculator
  def evaluate(rpn)
    rpn = rpn.split
    array = rpn.inject([]) do |array, i|
      if i.match(/\d+/)
        array = i.to_i
      else
        eq = array.pop(2)
        case
          when i == "+"
            array << eq[0] + eq[1]
          when i == "-"
            array << eq[0] - eq[1]
          when i == "*"
            array << eq[0] * eq[1]
        end
      end
    end
    puts array.pop
  end
end