Display two single array together

Question

I'm struggling here. My program is about a simple sign in and log in using array. Now, whenever I want to sign in, I want all the usernames and passwords to be displayed whenever I want to check if all the accounts I created are successfully collected in an array. Now whenever I want to display all the accounts, usernames aren't displaying, just the passwords. Here is my code:

    package login;
    import java.util.*;
    import static java.lang.System.out;
    
    public class login {
    
         public static void main(String [] args) {
            
             String user [] = new String [100];
             String pass [] = new String [100];
             int sign=0;
             
             boolean again=true, logAgain=true;
             Scanner scan = new Scanner (System.in);
             while(again) {
             out.println("[1]Sign-up\n[2]Log-in\n[3]Display Account?\n[4]Exit");
             out.print("Select: ");
             int a=scan.nextInt();
                if (a==1) {
                    again=false;
                    sign++;
                    out.print("Username: ");
                    user[sign]=scan.nextLine();
                    scan.nextLine();
                    out.print("Password: ");
                    pass[sign]=scan.nextLine();
                    out.println("Log in now? [Y/N] : ");
                    String b=scan.next();
                        if(b.equals("Y")||b.equals("y")) {
                            again=true;
                        } else {
                            again=false;
                            System.exit(0);
                        }
                    
                } else if(a==2){
                    again=false;
                    logAgain=true;
                        while(logAgain) {
                        out.print("Username: ");
                        String userU=scan.nextLine();
                        scan.nextLine();
                        out.print("Password: ");
                        String userP=scan.nextLine();
                        
                            if (userU.equals(user[sign])&&userP.equals(pass[sign])) {
                                out.println("You're logged in!");
                                logAgain=false;
                                out.println("Back to menu? [Y/N] : ");
                                String c=scan.next();
                                    
                                    if (c.equals("Y")||c.equals("y")) {
                                        again=true;
                                    } else {
                                        System.exit(0);
                                    }
                            }else if (!userU.equals(user[sign])&&userP.equals(pass[sign])) {
                                out.println("Invalid username or Password!");
                                logAgain=true;
                            }else {
                                again=true;
                                logAgain=false;
                                out.println("Please register first!");
                            }
                        }
                } else if (a==3) {
                    again=false;
                        
                        if (sign<1) {
                            out.println("\nNo account to display!\nPlease sign-up first.\n");
                            again=true;
                        } else {
                            System.out.println("");
                            System.out.printf("%-15s%10s\n","Username","Passwords");
                            for (int i = 1; i <=sign; i++) 
                            System.out.printf("%-15s%10s\n",user[i],pass[i]);
                            System.out.println("");
                            
                            out.println("Back to menu? [Y/N] : ");
                            String c=scan.next();
                            
                            if (c.equals("Y")||c.equals("y")) {
                                again=true;
                            } else {
                                System.exit(0);
                            }
                        }
                        
                } else if(a==4) {
                    again=false;
                    System.exit(0);
                } else {
                    
                }
         }
             
        }
}

And my output goes like this:

[1]Sign-up
[2]Log-in
[3]Display Account?
[4]Exit
Select: 3

Username        Passwords
                 Password
                     pass
                evohohivr

Back to menu? [Y/N] :

Thank you in advance.

Does this answer your question? [Scanner is skipping nextLine() after using next() or nextFoo()?](https://stackoverflow.com/questions/13102045/scanner-is-skipping-nextline-after-using-next-or-nextfoo) — Ken Y-N, May 27 '21 at 05:08
The issue may not be obvious from looking at the dup, but the problem really is there! Also, indexing arrays from `1` instead of `0` is a bad habit! — Ken Y-N, May 27 '21 at 05:10
@Ken Y-N okay I see, but is there any way for me to solve this. I'm stuck with this for a couple of hours and I just really want to know how can I solve this. — Sambajon Patrick, May 27 '21 at 05:16
The top answer on the dup describes two alternative workarounds; for this program I would suggest that after `int a=scan.nextInt();` you just add `scan.nextLine();`. This should get you going so you can focus on other issues like the Log-in option only working for the final user. — Ken Y-N, May 27 '21 at 05:21
@KenY-N It works!! Thank you so much, I'm gonna take your first advice about indexing array. Thank you. — Sambajon Patrick, May 27 '21 at 05:26
Allow me to suggest that you fix your problem by fixing your design. [Anti-pattern: parallel collections](https://codeblog.jonskeet.uk/2014/06/03/anti-pattern-parallel-collections/) on Jon Skeet’s code blog. — Ole V.V., May 27 '21 at 05:42

score 1 · Accepted Answer · answered May 27 '21 at 05:31

Your discarding the wrong Scanner input. It should read like this:

if (a==1) {
    again=false;
    sign++;
    out.print("Username: ");
    scan.nextLine();                 // This was the wrong order
    user[sign]=scan.nextLine();
    out.print("Password: ");
    pass[sign]=scan.nextLine();
    out.println("Log in now? [Y/N] : ");
    String b=scan.next();
    if(b.equals("Y")||b.equals("y")) {
        again=true;
    } else {
        again=false;
        System.exit(0);
    }            
}

Display two single array together

1 Answers1