static void Main(string[] args)
        {
            //Console.WriteLine("Hello World");
            Salutation walMartGreeter = new Salutation("Welcome to WalMart", "Thank you for shopping.");


            TestSalutationObject(walMartGreeter);

            Salutation klingonCommander = new Salutation("Pok' Mah!", "Q'plah!");
            TestSalutationObject(klingonCommander);
        }
        private static void TestSalutationObject(Salutation greeter)
        {
            string message;

            message = greeter.Greet();
            Console.WriteLine(message);
            message = greeter.Greet("Bob");
            Console.WriteLine(message);
            message = greeter.SayGoodbye();
            Console.WriteLine(message);
        }