Java - 纸牌游戏输出问题

Question

我很困惑为什么我的类(class)没有以正确的格式打印。当四只手都应该由不同的牌组成时，它只会为每只手打印相同的 Card 对象。

Answer 1

一个可运行的示例会很好，但快速阅读后我认为您的 if 语句实际上应该是 if-then-else，例如

//If there is a suit with 3 cards or more, return 0 points.
if ( c >=3 || d >= 3 || s >=3 || h >=3) {
    retVal = 0;
}  
//If there is a suit with 2 cards, return 1 points.
else if ( c == 2 || d == 2 || s == 2 || h == 2) {
    retVal = 1;
} 
//If there is a suit with 1 card, return 2 points.
else if ( c == 1 || d == 1 || s == 1 || h == 1) {
    retVal = 2;
}     
//If there is a suit with 0 cards, return 3 points.
else {
    retVal = 3;
}        

请注意末尾的 else - 因为您已经涵盖了大于 0 的所有内容，所以不需要在末尾测试 0。

编辑

你的代码可以被清理很多。代码越简洁，就越容易阅读。一些建议:

评论

您有很多注释，但您正在使用这些注释来弥补错误的变量名称!例如，

//Variable to hold number of cards that contain the club suit.
int c = 0;

这很好，但是当您稍后在代码中使用 c 时会怎么样？这不是不言自明的。首先为变量命名有意义的东西会更有用。

int clubs = 0;

枚举

不要使用字符来表示套装，而是使用枚举。它更好地体现了含义，并减少了拼写错误破坏代码的可能性，就像在字符串/字符上进行测试时可能发生的情况一样。

public enum Suit
{
    CLUBS,
    DIAMONDS,
    HEARTS,
    SPADES
}

对于每个循环

除非您需要索引变量，否则 foreach 循环更容易阅读。

 for (int i = 0; i < theHand.length; i++) {
     ...
 }

可以重写为

for (Card card : cards) {
    ...
}

缩小范围

在需要时而不是之前声明变量 - 这会缩小它们的范围，从而减少误用它们的机会。例如，

public int countDistributionPoints() {
    //Variable to hold the number of distribution points.
    int retVal = 0;

    // a whole bunch of stuff that doesn't use retVal

    //If there is a suit with 3 cards or more, return 0 points.
    if ( c >=3 || d >= 3 || s >=3 || h >=3) {
        retVal = 0;
    }  
    //etc

    return retVal;
}

您可以通过将 retVal 移动到使用它的位置来缩小它的范围。

public int countDistributionPoints() {
    // a whole bunch of stuff that doesn't use retVal

    //Variable to hold the number of distribution points.
    int retVal = 0;

    //If there is a suit with 3 cards or more, return 0 points.
    if ( c >=3 || d >= 3 || s >=3 || h >=3) {
        retVal = 0;
    }  
    //etc

    return retVal;
}

组合起来

重写您的 Hand 类以及一些 switch 语句和重命名的变量即可实现这一点。

public class Hand {
    private final Card[] cards;

    public Hand(Card[] cards) {
        this.cards = cards;
    }

    /**
     * Looks through each Card in the hand array and
     * adds its points (if it has any) to a sum.
     * @return the sum of the hand
    */
    public int countHighCardPoints() {
        int points = 0;
        for (Card card : cards) {
            points += card.getPoints();
        }
        return points;
    }

    /**
     * Count the number of Cards in each suit:
     * a suit with 3 cards or more counts for zero points
     * a suit with 2 cards counts one point (this is called a doubleton)
     * a suit with 1 card counts 2 points (this is called a singleton)
     * a suit with 0 cards counts 3 points (this is called a void)
     * @return the sum of the points
    */
    public int countDistributionPoints() {
        int clubs = 0;
        int diamonds = 0;
        int spades = 0;
        int hearts = 0;

        for (Card card : cards) {
            switch (card.getSuit()) {
                case CLUBS:
                    clubs++;
                    break;
                case DIAMONDS:
                    diamonds++;
                    break;
                case SPADES:
                    spades++;
                    break;
                case HEARTS:
                    hearts++;
                    break;
            }
        }

        final int result;
        if (clubs >= 3 || diamonds >= 3 || spades >= 3 || hearts >= 3) {
            result = 0;
        }
        else if (clubs == 2 || diamonds == 2 || spades == 2 || hearts == 2) {
            result = 1;
        }
        else if (clubs == 1 || diamonds == 1 || spades == 1 || hearts == 1) {
            result = 2;
        }
        else {
            result = 3;
        }

        return result;
    }

    public String toString() {
        String club = "";
        String diamond = "";
        String heart = "";
        String spade = "";

        for (Card card : cards) {
            switch (card.getSuit()) {
            case CLUBS:
                club.append(card.toString().replace(",", " "));
                break;
            case DIAMONDS:
                diamond.append(card.toString().replace(",", " "));
                break;
            case HEARTS:
                heart.append(card.toString().replace(",", " "));
                break;
            case SPADES:
                spade.append(card.toString().replace(",", " "));
                break;
        }
    }

    //Concatenates all of the string values of the clubs, diamonds, hearts, and spades into one string.
    return club + "\n" + diamond + "\n" + heart + "\n" + spade;
}

}