import java.util.LinkedList;

 import java.util.Random;

 //自定义一个Poker类，用于存储扑克的信息（花色、数字）

 class Poker{

     String color;

     String numbers;

     public Poker(String color, String numbers) {

         this.color = color;

         this.numbers = numbers;

     }

     //重写toString方法

     @Override

     public String toString() {

         return color + numbers;

     }

 }

 public class Demo3 {

     public static void main(String[] args) {

         LinkedList pokers = CreatePoker();

         shufflePoker(pokers);

         showPoker(pokers);

     }

     //生成一副扑克牌

     public static LinkedList CreatePoker(){

         LinkedList list = new LinkedList();

         String[] color = {"红桃","黑桃","梅花","方块"};

         String[] numbers = {"A","2","3","4","5","6","7","8","9","10","J","Q","K"};

         for (int i = 0; i < numbers.length; i++) {

             for (int j = 0; j < color.length; j++) {

                 list.add(new Poker(color[j], numbers[i]));

             }

         }

         return list;

     }

     //将扑克牌信息打印

     public static void showPoker(LinkedList pokers){

         for (int i = 0; i < pokers.size(); i++) {

             System.out.print(pokers.get(i) + " ");

             //为什么等于9？因为等于0的话，i为0时，直接换行打印。等于9是0 ~ 9，就是每十张牌变换行一次

             if(i % 10 == 9){

                 System.out.println();

             }

         }

     }

     //洗牌

     public static void shufflePoker(LinkedList pokers){

         Random random = new Random();

         for (int i = 0; i < 100; i++) { //i < 10也行，只不过原则上越大，牌洗得越乱

             int index1 = random.nextInt(pokers.size());

             int index2 = random.nextInt(pokers.size());

             Poker poker1 = (Poker) pokers.get(index1);

             Poker poker2 = (Poker) pokers.get(index2);

             pokers.set(index1, poker2);

             pokers.set(index2, poker1);

         }

     }

 }