public static void login_menu()
    {
        Scanner sc = new Scanner(System.in);
        File users = new File("Users.txt");
        int ok=0;
        String user,pass,info = null, next = null;
        String arr[]=null;

        System.out.println("Introduceti datele dumneavoastra: ");
        System.out.print("Nume utilizator: ");
        user = sc.nextLine();

        try
        {
            while(ok==0)
            {
                Scanner fs = new Scanner(users);
                while(fs.hasNextLine())
                {
                    info = fs.nextLine();
                    arr= info.split(" ", 3);
                    next = arr[0];
                    if(next.equalsIgnoreCase(user))
                    {
                        ok=1;
                        fs.close();
                        break;
                    }
                }

                if(ok == 0)
                {
                    System.out.print("Nu exista acest nume de utilizator, reintroduceti: ");
                    user = sc.nextLine();

                }
            }

            users = null;
            System.out.print("Introduceti parola: ");
            pass = sc.nextLine();
            next = arr[1];

            while(!next.contentEquals(pass))
            {
                System.out.println("Ati introdus parola gresita, reintroduceti: ");
                pass = sc.nextLine();
            }
            if(info.contains("seller"))
            {
                while(Vanzator.menu(user))
                {}
            }
            else if(info.contains("buyer"))
            {
                while(true)
                    Cumparator.menu();
            }
        }
        catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }