循环练习

package com.forkeon.test;

import java.util.Scanner;

import javax.swing.plaf.metal.OceanTheme;
//match.random 隨機數 4隨機數
// int number=(int)(math.random()(9999-1000))+1000
public class lianxi {
public static void main(String[] args) {
String answer="y";
boolean register=false; //注册标识位
boolean islogin=false;
String username="";
String password="";
do {
System.out.println("...歡迎進入獎客富翁系統...");
System.out.println("1.祖冊");
System.out.println("2.登錄");
System.out.println("3.抽獎");
System.out.println("......................................................");
Scanner input=new Scanner(System.in);
System.out.println("請選擇菜單");
int choice=input.nextInt();
switch (choice) {
case 1:
System.out.println("註冊");
System.out.println("請填寫個人信息");
System.out.println(" 用戶名");
username=input.next();
System.out.println("密碼");
password=input.next();
int number=(int)(Math.random()(9999-1000))+1000;
System.out.println("用戶名 密碼 會員卡號");
System.out.println(username+".."+password+"...."+number);
register=true;
break;
case 2:
System.out.println("登錄");
if (register) {
for(int i=1;i<=3;i++){
System.out.println("请输入登录名");
String inputname=input.next();
System.out.println("请输入密码");
String inputpassword=input.next();
if (inputname.equals(username)&&inputpassword.equals(password)) {
System.out.println("welcome"+username);
islogin=true;
break;
}else if(i<3){
System.out.println("您输入的密码不正确还有"+(3-i)+"次机会");
}else {
System.out.println("3次错误信息");
}
}
}else {
System.out.println("请先注册 在登录");
}
break;
case 3:
System.out.println("抽獎");
break;
default:
System.out.println("error..");
break;
}
System.out.println("是否繼續（y/n）");
answer=input.next();
} while (answer.equals("y"));

    if(answer.equals("n"));
    System.out.println("系統退出謝謝使用");
    
    
    
}

}