Question

Here’s the code

class RockPaperScissors

attr_reader :rock, :paper, :scissors, :determinant

def initialize
    @rock=1
    @paper=2
    @scissors=4
    @determinant=0
end

def play(param1, param2)
    @determinant = param1 + param2
    puts @determinant
end

end

Now this code is not complete, I need for the @determinant variable to actually be the sum of param1 and param2 to continue.

Here is an abbreviated summary of the command line activity

irb
source "rps2.rb"
rps = RockPaperScissors.new
rps.play(:scissors, :rock)

NoMethodError: undefined method '+' for :scissors:Symbol
from rps2.rb.rb:14:in 'play'
from (irb):23

Answer 1

If you have “attr_reader” you need to play this way:

rps.play(rps.scissors, rps.rock)

Another possible way to use symbols:

def initialize
    @hand = { :rock => 1, :paper => 2, :scissors => 4 }
    @determinant=0
end

def play(param1, param2)
    # check if params are correct

    puts @determinant = @hand[param1] + @hand[param2]
end