If you were to extend C with some OO elements

Not that there would be much point doing that and not just using a different language.
But I thought a little about things like classes with single inheritance (achieved by replicating the same code in the inheriting class as in the base one), and I wonder about ways to implement virtual functions. I thought that for each vfunction you could just store its pointer as an additional member, but then with multiple members a vtable would make for more efficient storage. And also, I could replace the vtable pointer with a pointer to some kind of a type descriptor (which would then have the vtable), and add some type of reflection.
But the latter two methods would have to add some kind of a ``hidden'' field to the struct, while in the first one the count and location of those fields would be predictable. If I went with the ``hidden pointer'' approach, I would then need to adjust pointers behind the scenes and some other shit. I wonder how C++ does this?

Also, your thoughts. And keep in mind that I'm not some kind of EXPERT LANGUAGE DESIGNER (at least not yet), so don't get too mad.

>>3
And, yes, sepples does just use virtual method tables, which you could find out by reading wikipedia for ten seconds.
As if I didn't know that, in ``I wonder how C++ does this?'', this = adjusting pointers.