I agree completely with Sneftel; be aware, however, that in C++, nested classes (subclassing is something very different, related to inheritance) don''t have a special relationship with enclosing classes, beyond being confined to their scope. This is very different from Java, for example, where an inner class has access to the outer class''s private data members and, unless declared static, instances of this are implicitly related to the instance of the outer class from which they were instantiated (which, IMO, is a very nice feature and one of the rather few times where I prefer the way Java handles something).