I would like to have a class which may have two different implementations which could be change during run time. In order to do so in a nice OO manner, I would have had to make two classes inheriting the original class and destroy and recreate the object in order to switch between the two implementations. This requires me to recreate the object which means recreating all the data within it, and that is time consuming. If there was a way to onky recreate the implementation part, without recreating the data part, and that the implementation part could still use the data part... Well, there is a way. But its not nice OO programming. The other way is to use pointers to functions and change the functions the pointers point to. Is there a way to do it in OO manner?

What you''re looking for is the strategy pattern. Google on "strategy pattern", e.g.: http://home.earthlink.net/~huston2/dp/strategy.html

And do yourself a favor and by this brilliant book:
Design patterns

Regards,
Andre (VizOne) Loker