Why isn't the 'combat' method working?

gistfile1.rb

class Fight

  def initialize
    Player.new
    Monster.new
  end #end of the initialize method.


  class Player
    attr_accessor :ac, :attack, :hp

      def initialize
        @ac = 12
	@attack = 5
	@hp = 20
      end #end of initialize method.

  end #end of the player class.

  class Monster
    attr_accessor :ac, :attack, :hp

    def initialize
      @ac = 10
      @attack = 4
      @hp = 15
    end #end of initialize method.
  end #end of monster class.
  
  def combat player, monster
    unless player.hp == 0 || monster.hp == 0
      if player.attack + rand(20) >= monster.ac
        monster.hp -= 1
      end #end of the if a hit 
    end #end of the unless checking for zero hp
  end #end of combat method.


end #end of the fight class.