How to implement lucky draw function in java

1. Task

Simulate the whole process of registration and login lucky draw

2. Main functions:

1.Registration
2.Login
3. Log out
4.Lottery
5.Log out of the system

Homepage:

1.Output menu
2.Select menu number
3. If the wrong number is selected, "Your input is wrong!" will be output.

Registration:

1. Enter the user name and password, and the system will generate a 4-digit random number as card number.
2. Registration is successful, output user information

Login:

1. Enter the user name and password used during registration, the login is successful, and the system prompts that the login is successful.
2. If the username and password are entered incorrectly, prompt the user to continue inputting.

Log out:

1. If the user is logged in, log out
2. If the user is not logged in, it will show that you are not logged in,

Lottery:

1. Enter the membership card number, and the system will generate 5 4-digit random numbers as lucky numbers
2. If the membership card number is one of them, you will become a lucky member today ; Otherwise, you are not a lucky member

Exit the system:

If the user wants to end the use of this system, he can exit the system and end the program.

Code implementation:

import java.util.Scanner;
 
class User{//用户
    String name;
    String password;
    int cardid;
    User(String name,String password){
        this.name=name;
        this.password=password;
        cardid=(int)(Math.random()*9000+1000);
    }
    String getName(){
        return name;
    }
    String getPassword(){
        return password;
    }
    int getCardid(){
        return cardid;
    }
}
public class Lottery {//抽奖系统
 
    public static void main(String[] args) {//main方法
        User[]user=new User[10];
        int total=0;//注册人数
        int j=0;//是否退出系统
        int x=0;//登录状态,默认未登录
        int y=-1;//当前登录用户元素
        do {
            System.out.println("*****欢迎进入幸运抽奖系统*****");
            System.out.println("\t1、注册");
            System.out.println("\t2、登录");
            System.out.println("\t3、退出登录");
            System.out.println("\t4、抽奖");
            System.out.println("\t5、退出系统");
            System.out.print("\t请选择：");
            int choice;
            Scanner reader=new Scanner(System.in);
            choice=reader.nextInt();
 
            switch (choice){
                case 1:
                    if (x==0)
                    total = getTotal(user, total);
                    else
                        System.out.println("您正在登录中，请先退出登录再注册！\n");
                    break;
                case 2:
                    if (x==0) {
                        int i = 0;
                        do {
                            y = toLogin(user, total);
                            if (y==-1) {
                                System.out.println("您的输入有误，请重新输入！\n");
                                i = 1;
                            }else {
                                x = 1;
                                i=0;
                            }
                        } while (i == 1);
                    }else
                        System.out.println("您正在登录中！\n");
                    break;
                case 3:
                    if (x==1){
                        x=0;
                        System.out.println("退出登录成功！\n");
                    }else
                        System.out.println("您未登录,请先登录！\n");
                    break;
                case 4:
                    if (x==1){
                        toLottery(user, y);
                    }else
                        System.out.println("您未登录,请先登录！\n");
                    break;
                case 5:
                    j=1;
                    break;
                default:
                    System.out.println("您的输出有误，请重新输入！\n");
            }
        }while(j!=1);
    }
 
    private static void toLottery(User[] user, int y) {//抽奖方法
        int j=0;
        System.out.println("本日幸运会员卡号为:");
        int cardid[]=new int[5];
        cardid[0]=(int)(Math.random()*9000+1000);
        cardid[1]=(int)(Math.random()*9000+1000);
        cardid[2]=(int)(Math.random()*9000+1000);
        cardid[3]=(int)(Math.random()*9000+1000);
        cardid[4]=(int)(Math.random()*9000+1000);
        for (int i=0;i<5;i++){
            System.out.print(cardid[i]+"  ");
            if(user[y].getCardid()==cardid[i]){
                j=1;
            }
        }
        System.out.println("\n您的会员卡号为：\n"+user[y].getCardid());
        if (j==1)
            System.out.println("恭喜您，成为本日的幸运会员！\n");
        else
            System.out.println("很遗憾，您不是本日幸运会员！\n");
    }
 
    private static int toLogin(User[] user, int total) {//登录方法
        Scanner reader=new Scanner(System.in);
        System.out.print("请输入您的用户名：");
        String name= reader.nextLine();
        System.out.print("请输入您的密码：");
        String password= reader.nextLine();
        int j=-1;
        for (int i = 0; i< total; i++) {
            if (name.equals(user[i].getName())) {
                if (password.equals(user[i].getPassword())) {
                    System.out.println("登陆成功!");
                    System.out.println("用户名："+name+"\n密码："+password+"\n会员号："+user[i].getCardid()+"\n");
                    j=i;
                }
            }
        }
        return j;
    }
    private static int getTotal(User[] user, int total) {//注册方法
        Scanner reader=new Scanner(System.in);
        System.out.print("请输入您的用户名：");
        String name= reader.nextLine();
        System.out.print("请输入您的密码：");
        String password= reader.nextLine();
        for (int i=0;i<total;i++) {
            if (name.equals(user[i].getName())) {
                System.out.println("用户名已存在，请重新输入！\n");
                return total;
            }
        }
        user[total]=new User(name,password);
        System.out.println("用户名："+name+"\n密码："+password+"\n会员号："+user[total].getCardid()+"\n");
        total++;
        return total;
    }
}

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