How do I use composition with inheritance?

Question

I\'m going to try to ask my question in the context of a simple example...

Let\'s say I have an abstract base class Car. Car has-a basic Engine object. I have a method

Answer 1

Do you have generics in your language? In Java I could do this:

class Engine {}

abstract class Car 
{
    private E engine;
    public E getEngine() { return engine; } 
}

class TurboEngine extends Engine {}

class Ferrari extends Car 
{
    // Ferrari now has a method with this signature:
    // public TurboEngine getEngine() {} 
}

I'm sure there's something similar in C#. You can then treat an instance of Ferrari as either an instance of the Ferrari subclass (with getEngine returning the TurboEngine) or as an instance of the Car superclass (when getEngine will return an Engine).