Prisoners dilemma algorithm-random player

I have a homework to make an algorithm of player, which will play a tournament, based on prisoners dilemma. Each game will have random iterations. I want to treat option, if my opponent in tournament will choose answer randomly .Every iteration, I can save opponent move in array(True=Defect, False=Cooperate). Does it exist some solution of my problem?

I would be grateful, if you can help me.