java - 从一副牌中洗牌和抽牌

Question

我正在尝试创建一个程序，要求用户从一副牌中洗牌或抽牌。它可以编译，但我遇到了一个主要问题:

在打印洗好的牌组或抽一张牌(根据我给出的命令)后，它不允许用户执行其他命令。

任何帮助将不胜感激。

代码如下:

import java.util.Random;
import java.util.Scanner;

public class Deck {

    static String [] number = {"Ace", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Jack", "Queen", "King"}; 
    static String [] suit = {"Clubs", "Hearts", "Diamonds", "Spades"}; 
    static String [] deck = new String[52]; 
    int cardsUsed = 0;

    public static void main (String [] args) {
        Deck d = new Deck(); 
        // print d.
        for (int i = 0;  i<number.length; i++) {
            for (int j = 0; j<suit.length; j++) {
                deck[13*j+i] = number[i] + " of " + suit[j];
            }
        }

        while (true) {
            System.out.println ("shuffle or draw");
            Scanner s = new Scanner(System.in); 
            System.out.println ("What would you like to do?"); 
            String command = s.next( ); 
            
            if (command.equals("shuffle")) {
                d.shuffle();
            } else if (command.equals("draw")){
                d.draw();
            } 

            s.close();
        }       
    }



    public void shuffle () {
        int k;
        Random shuffle = new Random();
        for (k = deck.length-1; k >= 0; k--){
            int index = Math.abs((shuffle.nextInt())%52);
            String temp = deck[k];
            deck[k] = deck[index];
            deck[index] = temp;
        }
        int l;
        for (l = 0; l<deck.length; l++){
            System.out.println (deck[l]);
        }
    }

    public void draw () {
        System.out.print (deck[cardsUsed]);

        if (cardsUsed < deck.length) {
            System.out.print (deck[cardsUsed]);
        } else {  
            System.out.println ("No cards are left in the deck.");  
            cardsUsed++;  
        }
    }

}

Answer 1

您只能发出一个命令的原因是您正在关闭扫描仪。文档位于 http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html#close()表示当您这样做时，它也会关闭底层流。因此，关闭扫描仪后，您将无法再获得任何输入。您应该将扫描仪初始化移到 while 循环之外，并且永远不要关闭它。