static void Main()
        {
            // member function is not static, thus it can be accessed only via object instantiation
            Chapter9Exercise1 objectInstantiation = new Chapter9Exercise1();

            objectInstantiation.GreetinsByName();
        }
        static void Main()
        {
            // member function is not static, thus it can be only accessed via object instantiation
            Chapter9Exercise1 objectInstantiation = new Chapter9Exercise1();

            objectInstantiation.GreetinsByName();
        }