JAVA练习题

题目：

编写一个洗牌的功能 使用list集合实现

方法一：

package com.qfstu.javase.Week03.Day01;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;


public class HomeWork03_1 {
    public static void main(String[] args) {
        List list = new ArrayList<>();

        for (int i = 1; i <= 13; i++) {
            list.add("♥" + i);
        }
        for (int i = 1; i <= 13; i++) {
            list.add("♠" + i);
        }
        for (int i = 1; i <= 13; i++) {
            list.add("♦" + i);
        }
        for (int i = 1; i <= 13; i++) {
            list.add("♣" + i);
        }

        //洗牌
        Random random = new Random();
        for(int i = 1; i <= 52; i++) {
            //随机产生两个索引值
            int a = random.nextInt(list.size());
            int b = random.nextInt(list.size());
            //根据索引值取出俩张牌，然后交换俩张牌的顺序
            String poker1 = list.get(a);
            String poker2 = list.get(b);
            list.set(a, poker2);
            list.set(b, poker1);
        }

        //发牌
        int i = 0;
        for (String s : list) {
            i++;
            System.out.print(s + "t");
            if(i % 13 == 0) {
                System.out.println();
            }
        }

    }
}

方法二：

package com.qfstu.javase.Week03.Day01;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;


public class HomeWork03_2 {
    public static void main(String[] args) {
        //牌存入集合
        List list = new ArrayList<>();
        String[] str1 = {"♠","♠","♣","♦"};
        String[] str2 = {"A","2","3","4","5","6","7","8","9","10","J","Q","K"};
        for (int i = 0; i < str1.length; i++) {
            for (int j = 0; j < str2.length; j++) {
                list.add(new Poker(str1[i],str2[j]));
            }
        }

        //洗牌
        Random random = new Random();
        for(int i = 1; i <= 52; i++) {
            //随机产生两个索引值
            int a = random.nextInt(list.size());
            int b = random.nextInt(list.size());
            //根据索引值取出俩张牌，然后交换俩张牌的顺序
            Poker poker1 = list.get(a);
            Poker poker2 = list.get(b);
            list.set(a, poker2);
            list.set(b, poker1);
        }
        //发牌
        int i = 0;
        for (Poker poker : list) {
            System.out.print(poker + "t");
            i++;
            if(i % (list.size()/4) == 0) {
                System.out.println();
            }
        }

    }
}

//定义扑克类
class Poker{
    private String color;
    private String num;

    //重写toString方法
    @Override
    public String toString() {
        return getColor() + getNum();
    }

    public Poker() {
    }

    public Poker(String color, String num) {
        this.color = color;
        this.num = num;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public String getNum() {
        return num;
    }

    public void setNum(String num) {
        this.num = num;
    }
}