動手寫了才對知識點有更深的感覺

再次體會到了Java是完全面向物件的語言，調動物件做事情

對迭代器的使用有了初步的認識

要遍歷ArrayList集合的話有2種方法

1.使用toarray功能轉為陣列，再進行遍歷

2.建立一個集合的迭代器,使用迭代器去遍歷集合

package 第15天;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.Scanner;

public class test1 {

    public static class User{
        int id;
        String password;
        public
 
 User(int id, String password) {
            this.id = id;
            this.password = password;
        }
        public int getId() {
            return id;
        }
        public void setId(int id) {
            this.id = id;
        }
        public String getPassword() {
            return password;
        }
        public
 
 void setPassword(String password) {
            this.password = password;
        }

        @Override
        public boolean equals(Object obj) {
            User user =  (User) obj;
            return this.id == user.id;
        }

        @Override
        public String toString() {
            // TODO Auto-generated method stub
 

            return "賬號：" + this.id + "密碼：" + this.password;
        }
    }

    static Scanner scanner = new Scanner(System.in);
    static ArrayList<User> users = new ArrayList<User>();


    public static void login(){
        System.out.println("請輸入賬號");
        int id = scanner.nextInt();
        System.out.println("請輸入密碼");
        String password = scanner.next();
        boolean isLogin = false;
        Iterator it = users.iterator();
        while(it.hasNext()){
            User user = (User) it.next();
            if(user.id == id && user.password.equals(password)){
                isLogin = true;
                System.out.println("登入成功！");
            }else{
                System.out.println("登入失敗！");
            }
        }
    }

    public static void reg(){
        User user = null;
        while(true){
            System.out.println("請輸入賬號");
            int id = scanner.nextInt();
            user = new User(id,null);
            if(users.contains(user)){
                System.out.println("已存在該賬號！");
            }else{
                break;
            }
        }
        System.out.println("請輸入密碼");
        String password = scanner.next();
        user.setPassword(password);
        users.add(user);
        System.out.println("註冊成功@");
        System.out.println("當前註冊的人員" + users);
    }

    public static void main(String[] args) {
        while(true){
            System.out.println("請選擇功能 A（註冊） B（登入）");
            String option = scanner.next();
            if("a".equalsIgnoreCase(option)){
                reg();
            }else if("b".equalsIgnoreCase(option)){
                login();
            }else{
                System.out.println("輸入有誤，請重新輸入");
            }
        }
    }

}