//public class SteelGuitar : GuitarBaseOptional, IGuitar<SteelGuitar>
        //{
        //    public string Name { get; set; }
        //    public string GetType(ClassicalGuitar t)
        //    {
        //        return "The classical guitar is: " + t.Name;
        //    }
        //}

        static void Main(string[] args)
        {
            ElectricGuitar eGuitar = new ElectricGuitar();

            eGuitar.Name = "Model 5";
            Console.WriteLine(eGuitar.GetType(eGuitar));
            eGuitar.Builder = "Charvel";
            Console.WriteLine("The builder is :" + eGuitar.Builder);
            Console.WriteLine("It was built on :" + eGuitar.GetBuildDate());
            eGuitar.Cost = 800;
            Console.WriteLine("It sold for :" + eGuitar.GetSoldFor().ToString());
            Console.WriteLine();

            ClassicalGuitar cGuitar = new ClassicalGuitar();

            cGuitar.Name = "C132S";
            Console.WriteLine(cGuitar.GetType(cGuitar));
            cGuitar.Builder = "Takamine";
            Console.WriteLine("The builder is :" + cGuitar.Builder);
            Console.WriteLine("It was built on :" + cGuitar.GetBuildDate());
            cGuitar.Cost = 350;
            Console.WriteLine("It sold for :" + cGuitar.GetSoldFor().ToString());

            Console.ReadLine();
        }