java - Java 中不允许声明变量

Question

这是我学校项目中的一个 java 扑克项目。

一开始定义了Card类。

class Card {

/* constant suits and ranks */
static final String[] Suit = {"Clubs", "Diamonds", "Hearts", "Spades" };
static final String[] Rank = {"","A","2","3","4","5","6","7","8","9","10","J","Q","K"};

/* Data field of a card: rank and suit */
private int cardRank;  /* values: 1-13 (see Rank[] above) */
private int cardSuit;  /* values: 0-3  (see Suit[] above) */

/* Constructor to create a card */
/* throw MyPlayingCardException if rank or suit is invalid */
public Card(int rank, int suit) throws MyPlayingCardException { 
if ((rank < 1) || (rank > 13))
    throw new MyPlayingCardException("Invalid rank:"+rank);
else
        cardRank = rank;
if ((suit < 0) || (suit > 3))
    throw new MyPlayingCardException("Invalid suit:"+suit);
else
        cardSuit = suit;
}

/* Accessor and toString */
/* You may impelemnt equals(), but it will not be used */
public int getRank() { return cardRank; }
public int getSuit() { return cardSuit; }
public String toString() { return Rank[cardRank] + " " + Suit[cardSuit]; }

然后，我尝试定义 Deck 类。但是我有一些错误。

class Decks {

/* this is used to keep track of original n*52 cards */
private List<Card> originalDecks;   

/* this starts with n*52 cards deck from original deck   */
/* it is used to keep track of remaining cards to deal */
/* see reset(): it resets dealDecks to a full deck      */
private List<Card> dealDecks;

/* number of decks in this object */
private int numberDecks;

  public Decks()
{
    ArrayList<Card> originalDecks = new ArrayList<Card>(52);
    ArrayList<Card> dealDecks = new ArrayList<Card>(52); 

     Card card = new Card(j,i);   //Error

    for (int i=0; i<=3; i++)  
        for (int j=0; j<= 13; j++)              

              originalDecks.add(card);   //Error

    dealDecks.addAll(originalDecks); 


}

公共(public)甲板(int n) {

    int numberDecks=n ; 

    Decks originalDecks = new Decks();

    for (int m=0; m< n; m++){

         originalDecks += originalDecks ; 

    }


}

想法是:首先，我尝试创建一副有 52 张牌的牌；然后我将它循环 n 次以创建 n 副牌。但是，我收到了一些 Unresolved 错误，向我展示了这一点

Cannot find symbol i, j.

这是为什么呢？

Answer 1

因为您尝试在定义i 和j 之前创建Card。另外，请使用大括号。

// Card card = new Card(j,i);
for (int i=0; i<=3; i++) {  
    for (int j=0; j<= 13; j++) {
        Card card = new Card(j,i);
        originalDecks.add(card); 
    }
}