public static void exampleList(List <SavingAccount> list)
        {
            DateTime date1 = DateTime.Now; DateTime date2 = date1.AddMonths(3);

            Address       address1 = new Address("FirstStreet", 1, "FirstCity", 12345);
            Client        client1  = new Client("Ed", "Small", 12345678910, address1);
            SavingAccount account1 = new SavingAccount(300, client1, date2, 2, 5);

            Address       address2 = new Address("SecondStreet", 1, "SecondCity", 23456);
            Client        client2  = new Client("Jim", "Big", 54345678910, address2);
            SavingAccount account2 = new SavingAccount(1000, client2, date2, 2, 6);

            list.Add(account1);
            list.Add(account2);
        }
        public static void addSavingAccount(List <SavingAccount> SavingAccountList, ref int idNumber)
        {
            SavingAccount nextAccount = new SavingAccount();

            nextAccount.setAccountDetails(ref idNumber);

            foreach (SavingAccount account in SavingAccountList)
            {
                if (account.AccountOwner.Pesel == nextAccount.AccountOwner.Pesel)
                {
                    Console.WriteLine("Error. Client with " + nextAccount.AccountOwner.Pesel + " PESEL has already had Current Accout.");
                    break;
                }
                else
                {
                    SavingAccountList.Add(nextAccount);
                    Console.WriteLine("Account has been created.");
                    break;
                }
            }
        }