(2)设计一副牌 Poker 的外部类和一张牌 Card 的内部类。 O Poker 类中定义私有成员花色数组、点数数组以及一副牌的数组属性，提供构造方法(创建并初始化一副牌的数组)随机洗牌方法 shuffle(Math.random()获取[0,1)的随机数;获取[n,m)的随机数公式为 Math,random()*(m-n)十n)和发牌方法 deal。@ Card 类中定义花色和点数属性,提供打印信息方法。O定义测试类并在 main()方法中创建一副牌 Poker 对象,并调用 shuffle()进行洗牌deal()进行发牌

Poker类：

public class Poker {
    private String[] suits = {"♠️", "♥️", "♣️", "♦️"};
    private String[] ranks = {"A", "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K"};
    private Card[] deck;

    public Poker() {
        deck = new Card[52];
        int index = 0;
        for (int i = 0; i < suits.length; i++) {
            for (int j = 0; j < ranks.length; j++) {
                deck[index++] = new Card(suits[i], ranks[j]);
            }
        }
    }

    public void shuffle() {
        for (int i = 0; i < deck.length; i++) {
            int j = (int) (Math.random() * (i + 1));
            Card temp = deck[i];
            deck[i] = deck[j];
            deck[j] = temp;
        }
    }

    public void deal() {
        for (int i = 0; i < deck.length; i++) {
            System.out.printf("%-3s", deck[i].toString());
            if ((i + 1) % 4 == 0) {
                System.out.println();
            }
        }
    }
    
    // 内部类 Card
    private class Card {
        private String suit;
        private String rank;

        public Card(String suit, String rank) {
            this.suit = suit;
            this.rank = rank;
        }

        public String getSuit() {
            return suit;
        }

        public String getRank() {
            return rank;
        }

        public String toString() {
            return rank + suit;
        }
    }
}

测试类：

public class PokerTest {
    public static void main(String[] args) {
        Poker poker = new Poker();
        poker.shuffle();
        poker.deal();
    }
}

运行结果：

J♠️  10♦️ 9♣️  8♥️  
2♠️  5♠️  4♦️  3♠️  
8♠️  5♥️  7♠️  4♠️  
Q♣️  A♣️  6♠️  K♠️  
9♥️  7♣️  3♣️  3♥️  
6♥️  2♥️  7♥️  J♥️  
2♣️  5♦️  4♥️  K♥️  
K♣️  10♣️ Q♥️  A♥️  
10♠️ A♦️  Q♦️  8♣️  
J♦️  7♦️  9♦️  6♦️  
5♣️  2♦️  J♣️  9♠️  
6♣️  K♦️  4♣️  3♦️  
Q♠️  A♠️  8♦️  10♥️