为什么这个数组列表被填充/打印了错误的值

Question

我已经写了3个类。一个是卡类，代表扑克牌：

public class Card 
{
    int theRank, theSuit, theCard;
    public Card(int suit, int rank)
    { 
     theRank = rank;
     theSuit = suit;
    }
    public String getRank()
    {
     String rankString = "";
     switch (theRank)
     {
         case 1:
             rankString = "Ace";
         case 2: 
             rankString = "2";
         case 3:
             rankString = "3";
         case 4:
             rankString = "4";
         case 5:
             rankString = "5";
         case 6:
             rankString = "6";
         case 7:
             rankString = "7";
         case 8:
             rankString = "8";
         case 9:
             rankString = "9";
         case 10:
             rankString = "10";
         case 11:
             rankString = "Jack";
         case 12:
             rankString = "Queen";
         case 13:
             rankString = "King";
      }
      return rankString;
    }
    public String getSuit()
    {
     String suitString = "";
     switch(theSuit)
     {
         case 1:
             suitString = "Diamonds";
         case 2:
             suitString = "Hearts";
         case 3:
             suitString = "Clubs";
         case 4:
             suitString = "Spades";
     }
     return suitString;
  }
}

另一个是类 Deck，它表示 Card 对象的数组列表：

public class Deck 
{
    public ArrayList<Card> loadDeck(ArrayList<Card> deck)
    {
     for (int suit = 1; suit <= 4; suit++)
     {
      for (int rank = 1; rank <= 13; rank++)
      {
       deck.add(new Card(suit, rank));
      }
     }
    return deck;
 }
public void printDeck(ArrayList<Card> deck)
{
    for (int i = 0; i <= deck.size(); i++)
    {
     Card temp = deck.get(i);
     String rank = temp.getRank();
     String suit = temp.getSuit();
     System.out.println(rank + " of " + suit);
    }
 }
 public void shuffleDeck(ArrayList<Card> deck)
 {
    Card temp;
    int index;
    Random rand = new Random();
    for (int i = deck.size() - 1; i > 0; i--)
    {
     index = rand.nextInt(i + 1);
     temp = deck.get(index);
     deck.add(index, deck.get(i));
     temp = deck.get(i);
    }
 }
public ArrayList dealHand(ArrayList<Card> deck)
{
    Random rand = new Random();
    ArrayList<Card> hand = new ArrayList<Card>(8);
    for (int i = 0; i <= 6; i++)
    {
     int suit = rand.nextInt(3);
     int rank = rand.nextInt(51);
     Card temp = new Card(suit, rank);
     hand.add(i, temp);
     deck.remove(temp);

    }
    return hand;
}
public void printHand(ArrayList<Card> hand)
{
    for (int i = 0; i <= 6; i++)
    {
     Card temp = hand.get(0);
     System.out.println(temp.getRank() + " of " + temp.getSuit());
    }
}
}

然后我有一个包含主方法的类 GoFish：

import java.util.ArrayList;
public class GoFish 
{
    public static void main(String[] args) 
    {
        Deck testDeck = new Deck();
        ArrayList<Card> deck = new ArrayList<Card>();
        deck = testDeck.loadDeck(deck);
        testDeck.printDeck(deck);
    }
}

我想要的输出是标准 52 副牌中每张牌的等级和花色。但是填充 arrayList 或打印列表时存在问题。有什么建议吗？

Answer 1

如@pbabcdefp所述，您的 switch 语句缺少其中断语句。如果没有中断，执行将通过最后一个 case 语句设置 rankString = "King"。这是切换到教程的链接

它应该是：

        switch (theRank) {
        case 1:
            rankString = "Ace";
            break;
        case 2:
            rankString = "2";
            break;
        case 3:
            rankString = "3";
            break;
        case 4:
            rankString = "4";
            break;
        case 5:
            rankString = "5";
            break;
        case 6:
            rankString = "6";
            break;
        case 7:
            rankString = "7";
            break;
        case 8:
            rankString = "8";
            break;
        case 9:
            rankString = "9";
            break;
        case 10:
            rankString = "10";
            break;
        case 11:
            rankString = "Jack";
            break;
        case 12:
            rankString = "Queen";
            break;
        case 13:
            rankString = "King";
            break;
        }

同样在方法printDeck（ArrayList）中，抛出了一个IndexOutOfBoundsException，因为像普通的Java数组一样，列表是从零开始索引的 https://docs.oracle.com/javase/7/docs/api/java/util/List.html#get（int）所以

for (int i = 0; i <= deck.size(); i++)

应该是

for (int i = 0; i < deck.size(); i++) 

Answer 2

case的每一端都需要break;