static void Main(string[] args)
        {
            CreditAccount cc = new CreditAccount();

            CreditAccount  c  = new CreditAccount("18-1", "MD Nabil Hossain", 10000);
            CurrentAccount cu = new CurrentAccount("18-2", "Fawaz Hossain", 10000);
            SavingsAccount s  = new SavingsAccount("18-3", "Famil Hossain", 10000);

            Boolean repit = true;

            while (repit)
            {
                Console.WriteLine("\n1. Show all Account details ");
                Console.WriteLine("2. Deposit ");
                Console.WriteLine("3. Withdraw ");
                Console.WriteLine("4. Exit  ");
                int option = Convert.ToInt32(Console.ReadLine());

                switch (option)
                {
                case 1:
                    c.show();
                    cu.show();
                    s.show();
                    break;

                case 2:
                    Console.WriteLine("Enter Account Number: ");
                    string AccountNumber = Console.ReadLine();
                    if (c.AccNumber == AccountNumber)
                    {
                        Console.WriteLine("Enter Depost Blance:");
                        Double balanceC = Convert.ToDouble(Console.ReadLine());
                        c.Deposit(balanceC);
                    }
                    else if (cu.AccNumber == AccountNumber)
                    {
                        Console.WriteLine("Enter Depost Blance:");
                        Double balanceC = Convert.ToDouble(Console.ReadLine());
                        cu.Deposit(balanceC);
                    }
                    else if (s.AccNumber == AccountNumber)
                    {
                        Console.WriteLine("Enter Fixed Depost Blance:");
                        Double balanceC = Convert.ToDouble(Console.ReadLine());
                        s.Deposit(balanceC);
                    }
                    else
                    {
                        Console.WriteLine("Invalid Account .");
                    }

                    break;

                case 3:
                    Console.WriteLine("Enter Account Number: ");
                    string AccountNumberW = Console.ReadLine();
                    if (c.AccNumber == AccountNumberW)
                    {
                        Console.WriteLine("Enter Withdraw Blance:");
                        Double balanceC = Convert.ToDouble(Console.ReadLine());
                        c.Withdraw(balanceC);
                    }
                    else if (cu.AccNumber == AccountNumberW)
                    {
                        Console.WriteLine("Enter Withdraw Blance:");
                        Double balanceC = Convert.ToDouble(Console.ReadLine());
                        cu.Withdraw(balanceC);
                    }
                    else if (s.AccNumber == AccountNumberW)
                    {
                        Console.WriteLine("Enter Withdraw Blance:");
                        Double balanceC = Convert.ToDouble(Console.ReadLine());
                        s.Withdraw(balanceC);
                    }
                    else
                    {
                        Console.WriteLine("Invalid Account .");
                    }

                    break;

                case 4:
                    Console.WriteLine("Exit ");
                    repit = false;
                    break;

                default:
                    Console.WriteLine("Invalid Input");
                    break;
                }
            }
        }