Hi Mark ----

There is certainly nothing wrong with 4 and I'd venture to say that an awful lot of coding is being done without abstract superclasses.

But think of it from the standpoint of messaging and implementation vs. interface. In a situation where an object has to blindly call a "vehicle", shouldn't it expect the same properties, events, and methods...that way the object need not know the type of vehicle?


> I would choose 4. The vehicle class is way too generic for the three subclasses. And if you further subclass the airplane,rowboat, and car classes those classes will have very little use for the vehicle superclass. So the Vehicle Superclass becomes nothing more than wasted resources. You end up with an object that's taking up more resources than it needs. On the other hand if you had the Vehicle Superclass you could overload the + operator and then
>airplane + rowboat = airboat. What do you think?
>