Java如何实现抽奖系统

package cn.jbit.dlc1;

import java.util.Scanner;

public class LuckyNumber5 {

 /**
  * 幸运抽奖
  */
 public static void main(String[] args) {
  String answer = "y"; // 标识是否继续
  String userName = ""; // 用户名
  String password = ""; // 密码
  int cardNumber = 0; // 卡号
  boolean isRegister = false; // 标识是否注册
  boolean isLogin = false; // 标识是否登录
  int max = 9999;
  int min = 1000;
  Scanner input = new Scanner(System.in);

  do {
   System.out.println("*****欢迎进入奖客富翁系统*****");
   System.out.println("\t1.注册");
   System.out.println("\t2.登录");
   System.out.println("\t3.抽奖");
   System.out.println("***************************");
   System.out.print("请选择菜单：");
   int choice = input.nextInt();
   switch (choice) {
   case 1:
    System.out.println("[奖客富翁系统 > 注册]");
    System.out.println("请填写个人注册信息：");
    System.out.print("用户名：");
    userName = input.next();
    System.out.print("密码：");
    password = input.next();
    // 获取4位随机数作为卡号
    cardNumber = (int)(Math.random()*(max-min))+min;
    System.out.println("\n注册成功，请记好您的会员卡号");
    System.out.println("用户名\t密码\t会员卡号");
    System.out.println(userName + "\t" + password + "\t" + cardNumber);
    isRegister = true; // 注册成功，标志位设置为true
    break;
   case 2:
    System.out.println("[奖客富翁系统 > 登录]");
    if (isRegister) { // 判断是否注册
     // 3次输入机会
     for (int i = 1; i <= 3; i++) {
      System.out.print("请输入用户名：");
      String inputName = input.next();
      System.out.print("请输入密码：");
      String inputPassword = input.next();
      if (userName.equals(inputName) && password.equals(inputPassword)) {
       System.out.println("\n欢迎您：" + userName);
       isLogin = true; // 登录成功，标志位设置为true
       break;
      } else if (i < 3) {
       System.out.println("用户名或密码错误，还有" + (3 - i) + "次机会！");
      } else {
       System.out.println("您3次均输入错误！");
      }
     }
    } else {
     System.out.println("请先注册，再登录！");
    }
    break;
   case 3:
    System.out.println("[奖客富翁系统 > 抽奖]");
    if (!isLogin) { // 判断是否登录
     System.out.println("请先登录，再抽奖！");
     System.out.println("继续吗？（y/n）");
     answer = input.next();
    } else {
     //生成5个4位随机数字，并保存在数组中
     int[] luckynums = new int[5];
     for(int i = 0; i < luckynums.length; i++){
      luckynums[i] = (int)(Math.random()*(max-min))+min;
     }
     System.out.print("请输入您的卡号：");
     int yourcard = input.nextInt();
     int i;
     System.out.print("\n本日的幸运数字为：");
     for (i = 0; i < luckynums.length; i++) {
      System.out.print(luckynums[i] + " ");
     }
     for (i = 0; i < luckynums.length; i++) {
      if (luckynums[i] == yourcard) {
       System.out.println("\n恭喜！您是本日的幸运会员！");
       break;
      }
     }
     if (i == luckynums.length) {
      System.out.println("\n抱歉！您不是本日的幸运会员！");
     }
    }
    break;
   default:
    System.out.println("[您的输入有误！]");
    break;
   }
   System.out.print("继续吗？（y/n）:");
   answer = input.next();
   System.out.println("");
  } while ("y".equals(answer));
  if ("n".equals(answer)) {
   System.out.println("系统退出，谢谢使用！");
  }
 }
}