Discussion on: Ruby Interview Tasks - Simple word calculator

  class One
    def initialize
      @num = 1
    end

    def plus
      @opt = :add
      return self
    end

    def minus
      @opt = :rmw
      return self
    end

    def two
      case @opt
        when :add then @num += 2
        when :rmw then @num -= 2
      end
      return self
    end

    def three
      case @opt
        when :add then @num += 3
        when :rmw then @num -= 3
      end
      return self
    end

    def equal
      num  = @num
      @num = 1
      return num
    end
  end

  one = One.new
  one.plus.two.equal    =>  3
  one.minus.three.equal => -2