数组、随机数、时间、字符串在购物系统中的应用

来源：互联网发布：linux telnet ip 端口编辑：程序博客网时间：2024/05/22 08:14

1．用数组实现存放多个用户名和密码

//定义一个字符串数组变量存放各个用户名import java.util.Scanner;//导入一个外部的java类String [] usernames = new String[10];usernames[0] = "admin1";usernames[1] = "admin2";usernames[2] = "admin3";usernames[3] = "admin4";usernames[4] = "admin5";usernames[5] = "admin6";usernames[6] = "admin7";usernames[7] = "admin8";usernames[8] = "admin9";usernames[9] = "admin10";String [] passwords = new String[10];passwords[0] = "1111";passwords[1] = "2222";passwords[2] = "3333";passwords[3] = "4444";passwords[4] = "5555";passwords[5] = "6666"; passwords[6] = "7777";passwords[7] = "8888";passwords[8] = "9999";passwords[9] = "0000";while(true) {Scanner input = new Scanner(System.in);System.out.println("请输入用户名：");String name = input.next();System.out.println("请输入密码：");String pass = input.next();for(int i = 0; i < usernames.length; i ++) {if(name.equals(usernames[i]) && pass.equals(passwords[i])) {System.out.println("登录成功");System.exit(1);}}System.out.println("登录失败");}

2.用java.util.Random;实现幸运抽奖

import java.util.Random;//产生随机数的外部java类    Random rand = new Random();int randNum = rand.nextInt(5) + 1;//随机产生一整数clientNum,(1 <= clientNum <= 5)int clientNum = 0;String clientName = null;String clientBirthday = null;int clientIntegral = 0;//客户积分switch(randNum){case 1:clientNum = 1001;clientName = "张三";clientBirthday = "1992-01-01";clientIntegral = 2000;break;case 2:clientNum = 1002;clientName = "李四";clientBirthday = "1991-08-02";clientIntegral = 2000;break;case 3:clientNum = 1003;clientName = "王五";clientBirthday = "1993-06-22";clientIntegral = 2000;break;case 4:clientNum = 1004;clientName = "赵六";clientBirthday = "1996-04-10";clientIntegral = 2000;break;case 5:clientNum = 1005;clientName = "陈七";clientBirthday = "1995-12-03";clientIntegral = 2000;break;}System.out.println("幸运的客户是：" + clientName);System.out.println("客户编号\t\t客户姓名\t\t客户生日\t\t客户积分\n");System.out.println(clientNum + "\t\t" + clientName +"\t\t" + clientBirthday + "\t\t" + clientIntegral +"\n");System.out.println("恭喜以上客户，获得价值￥18的黑人牙膏一支");System.out.println("请按任意键继续！");String arbi = input.next();if(arbi != "\r"){continue;}

3.用java.util.Calendar;java.text.SimpleDateFormat;和substring()方法实现当天是否是某客户的生日的判断

import java.util.Scanner;                            import java.util.Calendar;//导入一个外部的java类                            import java.text.SimpleDateFormat;Calendar d = Calendar.getInstance();//获取当天的日期SimpleDateFormat date = new SimpleDateFormat("MM-dd");String mmdd = date.format(d.getTime());//当天的日期，按MM-dd格式输出String clientName = "赵六";String clientBirthday = "1996-04-10";String md = clientBirthday.substring(5,clientBirthday.length());//MM-dd格式的生日if(md.equals(mmdd)){System.out.println("今天是" + clientName + "的生日！生日快乐！"); System.out.println("请按任意键继续！");String arbi = input.next();if(arbi != "\r"){continue;}}else{System.out.println("对不起，今天没有过生日的用户");System.out.println("请按任意键继续！");String arbi = input.next();if(arbi != "\r"){continue;}}

0 0