Ruby - nilClass的問題

Question

我無法正常工作。我得到的錯誤是：

114 in'numberstash'：未定義的方法'cards'爲零：Nilclass（無方法錯誤）。

這是一個二十一點遊戲。我花了幾個小時試圖修復這些代碼，包括製作一堆測試腳本來解決這個問題。但是，我沒有運氣。這工作對我的測試腳本，但它不會對當前的腳本工作：

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 

我的問題是，爲什麼我收到上面提到的錯誤？

Answer 1

無處不在，你使用player酒杯，你的意思是@player，例如在Blackjack#initialize：

@player = Player.new() 

和Blackjack#numberstash：

puts @player.cards 

@標識實例變量，通過attr_accessor訪問的各種事情。