用java基础知识、循环、双重循环、随机数实现幸运抽奖功能。

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！"); } } }