What if there was a NEW vb6

[kfcSmitty]

You mean "specific Duck-Class" (which my implementation doesn't need at all, to cover the scenario).

No, I mean the implementation of the duck interface or abstract class. Whether you need it or not, if you have a property of "can fly," "nurses young," "extinct," etc., that will each have an if statement you will need to modify if you implement a new class or a duck goes extinct. Instead of just updating the interface, you now need to hunt down everywhere you have these if statements and update them. Hardly maintainable.

Wich would be "hard-coding" as well... (in a specific class, which the example avoids)...

Not hard-coding, especially if you are loading up the ducks as extensions. The core of the interface isn't changing, the properties of the implementation are.

Not at all - in your case, you will have to locate the position to "change something"
(e.g. to be able to make a formerly non-flying "RubberDuck fly") this way:
- locate the "type of duck" in your Code (double-click on cRubberDuck for example)
- locate the correct "duck-behaviour"-Method of this Class (in this case Fly - or the Constructor)
Apply your changes in the appropriate Method.

In my case the thing works over the same steps (just starting with the behaviour you want to change):
- locate the "duck-behaviour" you plan to change (double-clicking on the bDuckFly-Class)
- locate the "type of duck" you will apply these changes to (over the Enum-Value)
Apply the changes in the appropriate Select Case.

Maybe it is my way of thinking, but when I want to modify the a property of "rubber duck" I go into the rubber duck and find the property. I wouldn't think "I want to modify the rubber duck, so let me find the class that houses the property."

A behaviour-Class is *not* Core-Code - one can easily inject another one also in the Factory, if you care to do so
(e.g. to implement a special "Flight-Mode" for RubberDucks in a separat, dedicated behaviour-class)

I completely disagree. If I have a system that is used to categorize ducks, and for some reason I'm not using some kind of database, but rather extensions that house the information, it is definitely a core change to update that information. Instead of simply dropping a DLL into the project folder or something, I now need to edit the source code to update.

Nope, absolutely not (and BTW, it was Funky, not Shaggy who provided the "Duck-Strategies").

Whoops, sorry for the mistake Shaggy/Funky! I'll update my post after this. As for your comment, I've added comments to every point I've made as to why I feel the way I do. Can you elaborate more than "absolutely not"? My quotes above show even more why his is more maintainable in a real-world scenario. Yours may be nicer in a "this will never change so my code is more readable" scenario, but we all know that is never the case.

Please enhance Funkys example about "Displaying on a Printer" -
then post the needed Diffs... I will then do the same on my example.

Olaf

Not sure if that is directed towards me or not. I have no idea to what you're referring.