Bill,

I don't think you're blind :)

For the average, run-of-the mill control, such as a button or textbox, there does not necessarily need to be an abstract layer. You can just create a class from the baseclasses that you always use. Now a framework might put another layer in there, so they can make changes to their highest level without (theoretically) breaking anything you might have changed in the other level they provide to you.

Here's an example where abstract could come into play (Mario's looks good, too). You could have an abstract class called vehicle, which defines certain things common to all types of vehicles. Then you could have subclasses for car, bus, truck, etc. The vehicle class itself would be abstract if you never wanted to create an instance of a vehicle directly.

>Hi Jim,
>I'm still missing it.
>Doesn't Mario's example just demonstrate the value of inheritance in sub-classes?
>I don't see how it demonstrates a need for an "abstract" class that never gets used.
>Or am I really blind?
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