public void CheckLogin()
        {
            int    accountNumber = default;
            string login         = default;
            int    pin           = default;

            //get input from user
            Console.Write("Enter Login : "******"Enter Pin : ");
            try
            {
                pin = System.Convert.ToInt32(Console.ReadLine());
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            //check if login info is correct
            accountNumber = cBLL.CheckLogin(login, pin);
            if (accountNumber == -1)
            {
                //if not then increment tries
                tries++;
                Console.WriteLine("Login failed!\nTry again");
            }
            else
            {
                //if login info is correct then let user go to menu
                MainMenu(accountNumber);
            }
        }