#230 – User-Defined Types Are First Class Citizens

When you create a user-defined reference type using the class keyword, that new type can be treated in the same way that you treat any built-in type in the .NET Framework.  You can create instances of the type and interact with it in the same way that you interact with built-in types.

            // Interacting with TimeSpan class
            TimeSpan ts = new TimeSpan(5, 3, 2);
            double ms = ts.TotalMilliseconds;
            TimeSpan dblIt = ts.Add(ts);

            // Interacting with my Dog class
            Dog buster = new Dog("Buster", 5);
            int age = buster.Age;