밑에 코드는 자바 배열을 이용한 로그인 하고 그걸 보여주는 프로그램 인데요, 2째줄에 넣으면 첫째줄로 입력되고 어쩔때는 3번째로 넘어가네요. 마지막에 서치 항목은 아예 에러가 나네요, 코드에는 에러가 없다고 나오는데 뭐가 문제일까요?

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public static void main(String[] args) {

    //varaible declaration 
    int i,choice,lid,cid,f;
    String uid,chid,sid;  
    String l1[]=new String[5]; 
    String l2[]=new String[6]; 
    String l3[]=new String[5]; 
    String l4[]=new String[5]; 


for(i=0;i<4;i++) { 
    l3[i]="empty"; 
        } 
for(i=0;i<3;i++) { 

    l4[i]="empty"; 
    } 
    do 
    { 
    f=0; //status of the machines 
        System.out.println("LAB STATUS"); 
        System.out.println("Lab # Computer Stations"); 
        System.out.print("1 "); 

        for(i=0;i<5;i++) { 
            System.out.print((i+1)+": "+l1[i]+" "); 
            } 
        System.out.println(); 
        System.out.print("2 "); 
        for(i=0;i<6;i++) 
        { 
            System.out.print((i+1)+": "+l2[i]+" "); 
            } 
        System.out.println(); System.out.print("3 "); 
        for(i=0;i<4;i++) { 
            System.out.print((i+1)+": "+l3[i]+" "); 
            } 
        System.out.println(); System.out.print("4 "); 
        for(i=0;i<3;i++) {
            System.out.print((i+1)+": "+l4[i]+" "); 
            } 
        System.out.println(); 
        Scanner sc=new Scanner(System.in); 
        System.out.println("MAIN MENU"); 
        System.out.println("0) Quit"); 
        System.out.println("1) Simulate login"); 
        System.out.println("2) Simulate logoff"); 
        System.out.println("3) Search"); 
        choice = sc.nextInt();//asking for user choice 
        if(choice == 0) { 
            System.exit(0); 
        } 
        else if(choice == 1) { 

            //taking input from user 
            System.out.println("Enter the 5 digit ID number of the user logging in:"); 
            uid=sc.next(); System.out.println("Enter the lab number the user is logging in from (1-4):"); 
            cid=sc.nextInt(); System.out.println("Enter computer station number the user is logging in to (1-6):"); 
            cid=sc.nextInt(); 
            if(cid==1) { 
                l1[cid-1]=uid; 
                } 

            else 
                if(cid==2) { 
                l2[cid-1]=uid; 
                } 
            else 
                if(cid==3) { 
                    l3[cid-1]=uid; 
                    } 
                else 
                    l4[cid-1]=uid; 
            } 
        else 
            if(choice == 2) { //taking input from user 
                System.out.println("Enter the 5 digit ID number of the user to find:"); 
                chid=sc.next(); 
                for(i=0;i<5;i++) { 
                    if(l1[i].equalsIgnoreCase(chid)) l1[i]="empty"; 
                    } 
                for(i=0;i<6;i++) { 
                        if(l2[i].equalsIgnoreCase(chid)) l2[i]="empty"; 
                        } 
                    for(i=0;i<4;i++) { 
                            if(l3[i].equalsIgnoreCase(chid)) l3[i]="empty"; 
                            } 
                    for(i=0;i<3;i++) { 
                        if(l4[i].equalsIgnoreCase(chid)) l4[i]="empty"; 
                        } 
                    System.out.println("User "+chid+" is logged off."); 
                    } else 
                        if(choice == 3) { //taking input from user 
                            System.out.println("Enter the 5 digit ID number of the user to find:"); 
                            sid=sc.next(); 
                            for(i=0;i<5;i++) { 

                                if(l1[i].equalsIgnoreCase(sid)) { 

                                    System.out.println("User "+sid+" logged in lab 1 in system "+(i+1)); f=1; break; 
                                    }
                                } 
                            for(i=0;i<6;i++) { 
                                    if(l2[i].equalsIgnoreCase(sid)) { 
                                        System.out.println("User "+sid+" logged in lab 2 in system "+(i+1)); 
                                    f=1; break; 
                                    } 
                                } 
                                for(i=0;i<4;i++) { if(l3[i].equalsIgnoreCase(sid)) { 
                                    System.out.println("User "+sid+" logged in lab 3 in system "+(i+1)); 
                                    f=1; break; 
                                    } 
                                } for(i=0;i<3;i++) { 
                                    if(l4[i].equalsIgnoreCase(sid)) { 
                                        System.out.println("User "+sid+" logged in lab 4 in system "+(i+1)); 
                                        f=1; break; 
                                        } 
                                    } 
                                if(f==0) { 
                                    System.out.println("None of the user Id is not logged into any computer station"); 
                                    f=0; 
                                    } 
                                } 
        }
    while(choice!=0); 
    } 

}

결과가 이렇게 나옵니다.