Java基础黑马程序员教材案例2.3、2.6代码详解 java

一、2.3超市购物程序

import java.util.Scanner; public class test2_3 {//超市购物程序 staticdouble cash=0.0; publicstatic double buy(){System.out.println("你要买什么？输入id"); Scanner scanner=new Scanner(System.in); int id=1; id=scanner.nextInt(); System.out.println("买多少份？"); int num=scanner.nextInt(); switch (id){default: System.out.println("输入的不是商品号"); break; case1: cash+=8.8*num; break; case 2: cash+=10.0*num; break; case 3: cash+=18.8*num; break; case 4: cash+=12.5*num; break; case 5: cash+=15.5*num; } returncash; } public static void main(String[] args) {buy(); Scanner scanner=new Scanner(System.in); String choicey="Y"; String choicen="N"; System.out.println("还要买吗？要买输入Y，不买输入N"); String ch=scanner.nextLine(); if(ch.equals(choicey)){cash=buy(); } else if(ch.equals(choicen)){System.out.println("总共花了"+cash); System.exit(1); } System.out.println("总共花了"+cash); } }

二、2.6登陆注册

import java.util.HashMap; import java.util.Scanner; public class test2_6 { staticHashMap message=new HashMap<>(); publicstatic void login(){System.out.println("这里是登陆界面"); System.out.println("请输入账号密码"); Scanner scanner=new Scanner(System.in); int number=scanner.nextInt(); Scanner scanner1=new Scanner(System.in); String password=scanner1.nextLine(); if(message.get(number).equals(password)){System.out.println("登陆成功"); } else {System.out.println("密码不对哦，或者账号不存在"); } } publicstatic void register(){System.out.println("这里是注册界面"); System.out.println("请输入账号和密码一行一个，账号不能重复,长度仅限6位数"); System.out.println("tips:账号纯数字，密码你随意"); System.out.println("先输入账号吧，宝儿"); Scanner scanner=new Scanner(System.in); intnumber=scanner.nextInt(); System.out.println("输密码"); Scanner scanner1=new Scanner(System.in); String password=scanner1.nextLine(); message.put(number, password); } public static void check(){System.out.println(message); } publicstatic void exit(){System.exit(0); } public static void main(String[] args) {while (true){System.out.println("这里是登陆注册案例"); System.out.println("请选择要做的操作："); System.out.println("1.登陆"); System.out.println("2.注册"); System.out.println("3.查看"); System.out.println("4.退出"); Scanner scanner=new Scanner(System.in); int choice=scanner.nextInt(); switch (choice){default: System.out.println("选错了。再来"); break; case 1: login(); break; case 2: register(); break; case 3: check(); break; case 4: exit(); break; } }} }