Calculator with paper tape side effects

calculator.rb

class Calculator

  # add two numbers with side effects to tape
  def add(number1, number2)
    sum = number1 + number2
    tape("#{number1} + #{number2}")
    tape("=\n#{sum}")
    sum
  end


  private

  # print stuff to paper tape
  def tape(message)
    puts message
  end

end


calculator = Calculator.new
calculator.add(1,3)

# ruby calculator.rb
# 1 + 3
# =
# 4