猜拳游戏项目（涉及知识点Scanner、Random、For、数组、Break、Continue等）

 package day03.d3.xunhuankongzhi;

 import java.util.Scanner;

 public class CaiQuan {

     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
         String[] arr = { "石头", "剪刀", "布" };
         while (true) {
             System.err.println("请选择你要出的手势:");
             int you;
             for(;;){
                 you = sc.nextInt();
                 if(you>=0&&you<3){
                     System.err.println("你出的是" + arr[you]);
                     break;
                 }else{
                     System.err.println("你出的手势无效,请重新选择你要出的手势！");
                     continue;
                 }
             }

             int comp = (int) (Math.random() * 3);
             System.err.println("电脑出的是:" + arr[comp]);
             padDuan(you, comp);
             System.err.println("是否继续下一局(Y/N)：");
             String str;
             boolean bool;
             for (;;) {
                 str = sc.nextLine();
                 if (str.equals("Y")) {
                     bool = true;
                     break;
                 } else if (str.equals("N")) {
                     bool = false;
                     break;
                 } else {
                     System.err.println("输入有误，请重新输入！是否继续下一局(Y/N)：");
                     continue;
                 }
             }

             if (bool) {

             } else {
                 break;
             }

         }
     }

     public static void padDuan(int x, int y) {
         if (x == y) {
             System.err.println("英雄所见略同！");
         } else if ((x == 0 && y == 1) || (x == 1 && y == 2)
                 || (x == 2 && y == 0)) {
             System.err.println("恭喜你，你赢了！");
         } else {
             System.err.println("很遗憾，你输了，请再接再厉！");
         }
     }
 }