I vote for #2 - best use of polymorphism -

#1 is inefficient
#3 and #4 defeat OOP


>Hi boys & girls ---
>
>Another design abstract problem. Let us say that we have a class called Airplane that's parent class is Vehicle. All Vehicles derived classes Move. How they move is quite different: Airplanes fly, Cars drive, and Rowboats are rowed. Which of the four approaches are taken:
>
>1) The Vehicle superclass has Fly,Drive,and Row methods. The implementation of these methods is at either superclass or class level.
>
>2) The Vehicle supports a Move method. The subclass defines Move as appropriate and returns a value indicating it flew,drove, or was rowed.
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>3) The subclasses have Fly, Drive, and Row methods as apppropriate; no Move or move specific methods are defined in the Vehicle superclass.
>
>4) We have *no* Vehicle superclass and each subclass of Airplane, Rowboat, and Car is it's own superclass.
>
>I currently strive for option 2 and used to use 4. Comments?