Ruby - nilClass的问题

Question

我无法让这个工作.我得到的错误是:

114''numberstash':未定义方法'cards'代表nil:Nilclass(无方法错误).

这是一个二十一点游戏.我花了几个小时试图修复这段代码,包括制作一堆测试脚本来解决这个问题.但是,我没有运气.这适用于我的测试脚本,但它不适用于当前脚本:

class Card
  attr_accessor :suit, :value

  def initialize(suit, value)
    @suit = suit
    @value = value
  end

  def to_s
    "#{value} of #{suit}"
  end
end

class Deck
  attr_accessor :cards

  def initialize(number_of_decks)
    @cards = []
    num = number_of_decks
    counter = 0
    while counter < num
      ['H','C', 'S', 'D'].product(['2','3','4','5','6','7','8','9','10','J','K','Q','A']).each do |arr|
        @cards << Card.new(arr[0], arr[1])
      end
      counter += 1
    end
  end
end

class Player
  attr_accessor :cards, :testvalue

  def initialize
    @cards = []
  end
end

class Dealer
  attr_accessor :cards

  @cards = []
end

class Blackjack
  attr_accessor :deck, :player, :dealer

  def calculate arr
    new = arr.map { |e| e[1] }
    sum = 0
    ace = 0
    new.each { |value|
      if value == 'A'
        sum += 1
        ace = 1
      elsif value.to_i == 0
        sum += 10
      else
        sum += value.to_i
      end
    }
    if ace = 1 && sum + 10 <= 21
      ace = 0
      sum = sum + 10
    end
  end

  def initialize
    deck = Deck.new(4)
    #@deck = @deck.shuffle
    player = Player.new()
    dealer = Dealer.new()
  end

  def dealcards
    #puts 'dealcards'
    #player.cards << deck.cards.pop
    #dealer.cards << deck.cards.pop
  end

  def start
    #dealcards
    #player_turn
    #dealer_turn
    #compare?
    #play again?
    numberstash
  end

  def numberstash
    #player.cards << deck.cards.pop
    puts player.cards
    #dealer.cards << deck.cards.pop
  end
end

game = Blackjack.new()
game.start

我的问题是,为什么我得到上述错误？

Answer 1

你使用的二十一点中的任何地方player,你的意思是@player,例如Blackjack#initialize:

@player = Player.new()

并且Blackjack#numberstash:

puts @player.cards

@识别实例变量,访问的事物种类attr_accessor.