static void Main(string[] args)
        {
            Console.WriteLine("SavingsAccount Test");

               SavingsAccount sa = new SavingsAccount(1000, 0.5M);
               Console.WriteLine("Initial balance is {0:C} " , sa.Balance);
               Console.WriteLine("Total Interest is {0:C} " , sa.CalculateInterestRate());
               sa.Credit(sa.CalculateInterestRate());
               Console.WriteLine("Final balance is {0:C} " , sa.Balance);

               Console.WriteLine();
               Console.WriteLine();

               Console.WriteLine("CheckingAccount Test");
               CheckingAccount ca = new CheckingAccount(1000M, 3.5M);
               Console.WriteLine("Initial balance is {0:C} ", ca.Balance);
               ca.Credit(100M);
               ca.Debit(50M);
               Console.WriteLine("Final balance is {0:C} ", ca.Balance);
        }
        static void Main(string[] args)
        {
            Console.WriteLine("SavingsAccount Test");

            SavingsAccount sa = new SavingsAccount(1000, 0.5M);

            Console.WriteLine("Initial balance is {0:C} ", sa.Balance);
            Console.WriteLine("Total Interest is {0:C} ", sa.CalculateInterestRate());
            sa.Credit(sa.CalculateInterestRate());
            Console.WriteLine("Final balance is {0:C} ", sa.Balance);

            Console.WriteLine();
            Console.WriteLine();


            Console.WriteLine("CheckingAccount Test");
            CheckingAccount ca = new CheckingAccount(1000M, 3.5M);

            Console.WriteLine("Initial balance is {0:C} ", ca.Balance);
            ca.Credit(100M);
            ca.Debit(50M);
            Console.WriteLine("Final balance is {0:C} ", ca.Balance);
        }