Question

我正在创建一个包含多个课程的纸牌游戏。目前，我正在使用全局变量来保存$shuffled_deck，$players_hand和$dealers_hand变量，但我担心使用全局变量（可能是不必要的）并且更喜欢使用实例变量。

我一直在看书，但没有什么是真的点击。任何人都可以帮我指出正确的方向吗？

使用实例变量我无法保存@players_hand和@dealers_hand以便能够在其他类中使用它们。例如，我@players_hand类Player。我让Dealer类绘制了一张卡片，但是我无法将@players_hand拉到Dealer类中以将两者合二为一。

我目前的代码是：

class Blackjack

  def initialize
    @player = Player.new
    @dealer = Dealer.new
  end
end

class Dealer

  def initialize
    @deck = Deck.new
    $dealers_hand = 0
  end

  def hit_dealer
    @deck.hit_dealer
  end

  def hit_player
    @deck.hit_player
  end

  def draw_card
    @hit = $shuffled_deck
  end

  def shuffle
    @deck.suits
  end
end

class Player

  def initialize
    $players_hand = 0
  end   
end

class Deck

 def suits
   #code that shuffled the deck..
   $shuffled_deck = @shuffled_deck
 end

 def hit_player
   @hit = $shuffled_deck.pop
 end

 def hit_dealer
   @hit = $shuffled_deck.pop
 end

end

Answer 1

使用你的例子，你可以这样做

class Blackjack
  attr_reader :player, :dealer

  def initialize
    @player = Player.new
    @dealer = Dealer.new
  end
end

class Dealer
  def dealers_hand #the long java way of a getter
    @dealers_hand
  end

  #and now the short ruby way
  attr_reader :dealers_hand #if you only need to read the attribute
  attr_writer :dealers_hand #if you only need to write the attribute
  attr_accessor: dealers_hand #if you need both

  def initialize
    @deck = Deck.new
    @dealers_hand = 5
  end

  def hit_dealer
    @deck.hit_dealer
  end

  def hit_player
    @deck.hit_player
  end

  def draw_card
    @hit = $shuffled_deck
  end

  def shuffle
    @deck.suits
  end
end

class Player
  attr_reader :players_hand
  def initialize
    @players_hand = 0
  end   
end

class Deck

 def suits
   attr_reader :shuffled_deck
   @shuffled_deck = @shuffled_deck
 end

 def hit_player
   @hit = $shuffled_deck.pop
 end

 def hit_dealer
   @hit = $shuffled_deck.pop
 end

end

game = Blackjack.new
p game.dealer.dealers_hand
game.dealer.dealers_hand = 4
p game.dealer.dealers_hand

Answer 2

您想使用attr_reader，attr_writer或attr_accessor。以下是它们的工作原理：

attr_reader :players_hand：允许您编写some_player.players_hand以获取该播放器players_hand实例变量的值
attr_writer :players_hand：允许您编写some_player.players_hand = 0以将变量设置为0
attr_accessor :players_hand：允许您同时读写，就像您同时使用attr_reader和attr_writer一样。

顺便说一句，所有这些都是为您编写的方法。如果你愿意，你可以像这样手动完成：

class Player
  def initialize
    @players_hand = 0
  end  

  def players_hand
    @players_hand
  end

  def players_hand=(new_value)
    @players_hand = new_value
  end
end

如何在Ruby类之间传递变量？

2 个答案: