ed after its
declaration. This seems odd at first because it reads like an initial value.
It makes more sense if you see it as meaning that the method has a null
address.</p>

<p>A class is abstract if one or more of its methods is abstract.</p>

<p>It is illegal to create an object of an abstract class. You can only use it
as a baseclass to a derivation that overloads all of the abstract methods.
Only when all the abstract methods are overloaded by non-abstract methods does
the derived class itself become 