Question

我最近开始尝试自学一些基本的Java。我决定参与的第一个项目之一是一个简单的二十一点程序。我正在为游戏创建一些基本结构（我还没有对程序的实际游戏组件做任何事情）而且我还没有能够让我的shuffleDeck方法返回值。

我查看了各种互联网资源，甚至与其他一些功能性二十一点程序交叉引用，我仍然无法找到我的错误。当我运行main方法时，它应该洗牌并将其打印出来。有人可以帮忙吗？我有一个卡片类，一个甲板类和一个主要的二十一点类。它们是分开的，但我把它们全部集中在一起。

public class Card {

private String suit;
private String name;
private int value;


public Card(String nameOfCard, int gameValue,String nameOfSuit){    
    value = gameValue;
    suit = nameOfSuit;
    name = nameOfCard;
}

String getSuit(){

    return suit;
}

String getName(){

    return name;    
}

int getValue(){

    return value;
}


}


public class Deck {

private Card[] cardDeck;

public Deck(){

    cardDeck = new Card[52];
    cardDeck[0]= new Card("Two",2,"Diamonds");
    cardDeck[1]= new Card("Three",3,"Diamonds");
    cardDeck[2]= new Card("Four",4,"Diamonds");
    cardDeck[3]= new Card("Five",5,"Diamonds");
    cardDeck[4]= new Card("Six",6,"Diamonds");
    cardDeck[5]= new Card("Seven",7,"Diamonds");
    cardDeck[6]= new Card("Eight",8,"Diamonds");
    cardDeck[7]= new Card("Nine",9,"Diamonds");
    cardDeck[8]= new Card("Ten",10,"Diamonds");
    cardDeck[9]= new Card("Jack",10,"Diamonds");
    cardDeck[10]= new Card("Queen",10,"Diamonds");
    cardDeck[11]= new Card("King",10,"Diamonds");
    cardDeck[12]= new Card("Ace",11,"Diamonds");
    cardDeck[13]= new Card("Two",2,"Hearts");
    cardDeck[14]= new Card("Three",3,"Hearts");
    cardDeck[15]= new Card("Four",4,"Hearts");
    cardDeck[16]= new Card("Five",5,"Hearts");
    cardDeck[17]= new Card("Six",6,"Hearts");
    cardDeck[18]= new Card("Seven",7,"Hearts");
    cardDeck[19]= new Card("Eight",8,"Hearts");
    cardDeck[20]= new Card("Nine",9,"Hearts");
    cardDeck[21]= new Card("Ten",10,"Hearts");
    cardDeck[22]= new Card("Jack",10,"Hearts");
    cardDeck[23]= new Card("Queen",10,"Hearts");
    cardDeck[24]= new Card("King",10,"Hearts");
    cardDeck[25]= new Card("Ace",11,"Hearts");
    cardDeck[26]= new Card("Two",2,"Clubs");
    cardDeck[27]= new Card("Three",3,"Clubs");
    cardDeck[28]= new Card("Four",4,"Clubs");
    cardDeck[29]= new Card("Five",5,"Clubs");
    cardDeck[30]= new Card("Six",6,"Clubs");
    cardDeck[31]= new Card("Seven",7,"Clubs");
    cardDeck[32]= new Card("Eight",8,"Clubs");
    cardDeck[33]= new Card("Nine",9,"Clubs");
    cardDeck[34]= new Card("Ten",10,"Clubs");
    cardDeck[35]= new Card("Jack",10,"Clubs");
    cardDeck[36]= new Card("Queen",10,"Clubs");
    cardDeck[37]= new Card("King",10,"Clubs");
    cardDeck[38]= new Card("Ace",11,"Clubs");
    cardDeck[39]= new Card("Two",2,"Spades");
    cardDeck[40]= new Card("Three",3,"Spades");
    cardDeck[41]= new Card("Four",4,"Spades");
    cardDeck[42]= new Card("Five",5,"Spades");
    cardDeck[43]= new Card("Six",6,"Spades");
    cardDeck[44]= new Card("Seven",7,"Spades");
    cardDeck[45]= new Card("Eight",8,"Spades");
    cardDeck[46]= new Card("Nine",9,"Spades");
    cardDeck[47]= new Card("Ten",10,"Spades");
    cardDeck[48]= new Card("Jack",10,"Spades");
    cardDeck[49]= new Card("Queen",10,"Spades");
    cardDeck[50]= new Card("King",10,"Spades");
    cardDeck[51]= new Card("Ace",11,"Spades");

}

public void shuffleDeck(){

    Card temp;
    int num;

        for(int k = 0;k<3000;k++)
        {   
            num = (int)Math.random()*52;
            temp = cardDeck[num];
            cardDeck[num]=cardDeck[0];
            cardDeck[0]=temp;
        }

    }

void printDeck(){

    for(int t = 0;t<52;t++){
        System.out.println(cardDeck[t].getName() + " of " + cardDeck[t].getSuit());
    }
        }
            }

public class BlackJack {

public static void main(String[] args){ 

    Deck cards = new Deck();
    cards.shuffleDeck();
    cards.printDeck();

        }
            }

Answer 1

我看到的第一件事是(int)Math.random()*52将总是评估为0.你基本上生成一个介于0和1之间的数字，切断逗号之后的所有内容（通过强制转换为int），所以你总是得到一个0然后你乘以52无效。你想要(int)(Math.random()*52)。这样你首先乘以然后再施法。更好的是，使用Random类生成所需范围内的数字，或者更好的是，只需改为Collections.shuffle(Arrays.asList(cardDeck));。

Answer 2

首先我会尝试使用：

Collections.shuffle(Arrays.asList(cardDeck));

而不是实现shuffle方法。为什么重新发明轮子？

Answer 3

这一行失败了：num = (int)Math.random()*52;就像你立刻投了一样！将其更改为num = (int) (Math.random() * 52);

这是固定版本：

public class Card {

private String suit;
private String name;
private int value;

public Card(String nameOfCard, int gameValue,String nameOfSuit){    
    value = gameValue;
    suit = nameOfSuit;
    name = nameOfCard;
}

String getSuit(){

    return suit;
}

String getName(){

    return name;    
}

int getValue(){

    return value;
}


}

 class Deck {

private Card[] cardDeck;

public Deck(){

    cardDeck = new Card[52];
    cardDeck[0]= new Card("Two",2,"Diamonds");
    cardDeck[1]= new Card("Three",3,"Diamonds");
    cardDeck[2]= new Card("Four",4,"Diamonds");
    cardDeck[3]= new Card("Five",5,"Diamonds");
    cardDeck[4]= new Card("Six",6,"Diamonds");
    cardDeck[5]= new Card("Seven",7,"Diamonds");
    cardDeck[6]= new Card("Eight",8,"Diamonds");
    cardDeck[7]= new Card("Nine",9,"Diamonds");
    cardDeck[8]= new Card("Ten",10,"Diamonds");
    cardDeck[9]= new Card("Jack",10,"Diamonds");
    cardDeck[10]= new Card("Queen",10,"Diamonds");
    cardDeck[11]= new Card("King",10,"Diamonds");
    cardDeck[12]= new Card("Ace",11,"Diamonds");
    cardDeck[13]= new Card("Two",2,"Hearts");
    cardDeck[14]= new Card("Three",3,"Hearts");
    cardDeck[15]= new Card("Four",4,"Hearts");
    cardDeck[16]= new Card("Five",5,"Hearts");
    cardDeck[17]= new Card("Six",6,"Hearts");
    cardDeck[18]= new Card("Seven",7,"Hearts");
    cardDeck[19]= new Card("Eight",8,"Hearts");
    cardDeck[20]= new Card("Nine",9,"Hearts");
    cardDeck[21]= new Card("Ten",10,"Hearts");
    cardDeck[22]= new Card("Jack",10,"Hearts");
    cardDeck[23]= new Card("Queen",10,"Hearts");
    cardDeck[24]= new Card("King",10,"Hearts");
    cardDeck[25]= new Card("Ace",11,"Hearts");
    cardDeck[26]= new Card("Two",2,"Clubs");
    cardDeck[27]= new Card("Three",3,"Clubs");
    cardDeck[28]= new Card("Four",4,"Clubs");
    cardDeck[29]= new Card("Five",5,"Clubs");
    cardDeck[30]= new Card("Six",6,"Clubs");
    cardDeck[31]= new Card("Seven",7,"Clubs");
    cardDeck[32]= new Card("Eight",8,"Clubs");
    cardDeck[33]= new Card("Nine",9,"Clubs");
    cardDeck[34]= new Card("Ten",10,"Clubs");
    cardDeck[35]= new Card("Jack",10,"Clubs");
    cardDeck[36]= new Card("Queen",10,"Clubs");
    cardDeck[37]= new Card("King",10,"Clubs");
    cardDeck[38]= new Card("Ace",11,"Clubs");
    cardDeck[39]= new Card("Two",2,"Spades");
    cardDeck[40]= new Card("Three",3,"Spades");
    cardDeck[41]= new Card("Four",4,"Spades");
    cardDeck[42]= new Card("Five",5,"Spades");
    cardDeck[43]= new Card("Six",6,"Spades");
    cardDeck[44]= new Card("Seven",7,"Spades");
    cardDeck[45]= new Card("Eight",8,"Spades");
    cardDeck[46]= new Card("Nine",9,"Spades");
    cardDeck[47]= new Card("Ten",10,"Spades");
    cardDeck[48]= new Card("Jack",10,"Spades");
    cardDeck[49]= new Card("Queen",10,"Spades");
    cardDeck[50]= new Card("King",10,"Spades");
    cardDeck[51]= new Card("Ace",11,"Spades");

}

public void shuffleDeck(){

    Card temp;
    int num;

        for(int k = 0;k<3000;k++)
        {   
            num = (int) (Math.random() * 52);
            temp = cardDeck[num];
            cardDeck[num]=cardDeck[0];
           cardDeck[0]=temp;

        }

    }

void printDeck(){

    for(int t = 0;t<52;t++){
        System.out.println(cardDeck[t].getName() + " of " + cardDeck[t].getSuit());
    }
        }
            }

public class BlackJack {

public static void main(String[] args){ 

    Deck cards = new Deck();
    cards.shuffleDeck();
    cards.printDeck();

        }
            }

enter image description here

无法让我的二十一点程序打印一个洗牌版的牌组

3 个答案: