Trass3r wrote:
I only see two differences with abstract classes: interfaces can't
have instance (and class?) variables and you can inherit from multiple
interfaces. Am I missing something? Is this really necessary? Isn't
abstract classes enough? Does this have similar problems (or the same)
as multiple inheritance?
Yeah, providing default functionality that can be overridden is exactly
what abstract classes are for.
Abstract classes are a kludge meant to put state in a partially
implemented class. I don't think mentioning abstract classes is a
counter-argument to defining methods to interfaces.
Interfaces were introduced to circumvent all those multiple inheritance
problems!
Yes; a problem that abstract classes are not solving.
Andrei
