java - 向玩家数组列表发一张牌

Question

我正在尝试使用 ArrayList 构建一个二十一点纸牌游戏。我无法弄清楚向所有玩家发一张牌的逻辑——我认为我的问题与使用迭代器有关......

问题出在 GameRunner 的//发牌部分。我知道我没有正确使用 itr 为 ArrayList 中的每个玩家分配一张新卡。

import java.util.*;

public class GameRunner {

public static void main(String[] args) {

    int numDecks = Integer.parseInt(args[0]);;
    int numPlayers = Integer.parseInt(args[1]);
    String pName;

    //init
    Scanner sc = new Scanner(System.in);
    Deck gameDeck = new Deck(numDecks, true);
    List<Player> players = new ArrayList<>();

    players.add(new Player("Dealer"));

    //create players
    do{
        System.out.print("Enter an name of a player:  ");
        pName = sc.next();
        players.add(new Player(pName));
        numPlayers--;
    }while( numPlayers > 0);

    System.out.println(players.toString());


    //deal cards
    ListIterator<Player> itr = (ListIterator<Player>) players.iterator();
    while (itr.hasNext()){
      itr.drawCard(gameDeck.dealNextCard());
    }

  }//end main

}//end GameRunner class

...

来自玩家类别:

    public boolean drawCard(Card aCard){

    //print error if player is already at the card max
    if(this.numCards == MAX_CARDS){
        System.err.printf("%s's hand already has " + MAX_CARDS + 
                "cannot add another card\n", this.name);
        System.exit(1);
    }
    //add new card in the next slot and increment the number of cards
    this.hand[this.numCards] = aCard;
    this.numCards++;

    return (this.getHandSum() <= 21);
}

来自 Deck 类

    public Card dealNextCard(){ 
    if (numCards == 0){
        System.err.print("Too Few Cards to Deal another card");
        System.exit(1);
    }
    this.numCards--;
    return mCards.pop(); 
}

Answer 1

在使用迭代器的部分中，使用以下内容:

// deal cards
for (Player p : players) {
  p.drawCard(gameDeck.dealNextCard());
}

这个for (Player p : players)称为增强for 循环，有时也称为for-each 循环。它循环遍历 Iterable 中的每个项目。目的。安Iterable object 是一个实现 Iterable 的对象界面。

players ，其类型为 ArrayList<Player> ，实现Iterable<Player>接口(interface)，因此可以在增强的 for 循环中使用。

我上面使用的增强 for 循环相当于以下内容:

Iterator<Player> iter = players.iterator();
while (iter.hasNext()) {
  Player p = iter.next(); // this statement is what your code was missing
  p.drawCard(gameDeck.dealNextCard());
}

以下是有关增强 for 循环的 Oracle 教程的链接:http://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html

希望这有帮助!