gistfile1.txt

class RPNCalculator
  def evaluate(string)
    @pusher = []
    @solver = 0
    @string_breakdown = string.split
    @string_breakdown.map! do |item| 
      if item != '+' && item != '-' && item != '*' 
        item.to_i
      else
        item
      end
    end
    @string_breakdown.each do |op|
      if op != "+" && op != "-" && op != "*"
        @pusher << op
      elsif op == "+"
        @operands = @pusher.pop 2
        @solver = @operands.first + @operands.last
        @pusher << @solver
      elsif op == "-"
        @operands = @pusher.pop 2
        @solver = @operands.first - @operands.last
        @pusher << @solver
      elsif op == "*"
        @operands = @pusher.pop 2
        @solver = @operands.first * @operands.last
        @pusher << @solver
      end
    end
    @pusher.first.to_i
  end
end