JAVA 멤버관리(아이디/비밀번호), 배열과 객체 이용하기

package Exam06_14;
 
public class Member {
    String  name , id , pw;
    int     status; // 현재 로그인상태.. 1:로그인상태 0:로그아웃
    public Member(String n , String i,String pw)
    {
        name = n;
        id = i;
        this.pw = pw;
        status = 0;
    }   
 
}
 
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package Exam06_14;
 
import java.util.Scanner;
 
public class MemberService {
    static Member[] UserList = new Member[100];     
    static Scanner scanner = new Scanner(System.in);
     
    public int login(String id , String pw)
    {
        int     i;
        for(i=0;i<UserList.length;i++) {
            if (UserList[i]==null) break;
            if (UserList[i].id.equals(id) && 
                    UserList[i].pw.equals(pw)) {
                if (UserList[i].status==1) return(0);
                UserList[i].status = 1;             
                return(1);
            }
        }
        return (-1);
    }
    public void logout(String id)
    {
        int     i;
        for(i=0;i<UserList.length;i++) {
            if (UserList[i]==null) break;
            if (UserList[i].id.equals(id) && UserList[i].status==1) {
                UserList[i].status = 0;
                System.out.println(UserList[i].name+"님이 로그아웃하셨습니다.");
            }       
        }
    }
     
    public static void main(String[] args) {
        MemberService member = new MemberService();
        UserList[0] = new Member("홍길동","hong","12345");
        UserList[1] = new Member("고길동","gogi","23456");
        UserList[2] = new Member("테스트","test","45678");
         
        do {
            System.out.print("0:종료, 1:로그인선택 , 2:로그아웃 = ?"); 
            int choice = scanner.nextInt();
            if (choice==0) break;
            if (choice==1) {
                System.out.print("사용자 ID = ");
                String id = scanner.next();
                System.out.print("사용자 PW = ");
                String pw = scanner.next();
                int result = member.login(id,pw);
                if (result==1) {
                    System.out.println("로그인되었습니다.");
                } else if (result==0) {
                    System.out.println("이미 로그인 되어있습니다.");
                } else {
                    System.out.println("id 또는 패스워드가 정확하지않습니다.");
                }   
            }
            if (choice==2) {
                System.out.print("사용자 ID = ");
                String id = scanner.next();
                member.logout(id);
            }   
        }while(true);
    }
}