I used to know it very well. Now, not as much. Even when I wrote C++, I basically wrote "C, with classes."
Why write C-with-classes if you can just write C-with-structures-and-function-pointers instead?
Also, you may be giving up a lot of niceties in your IDE that way.
Plus, if there's some feature of C++ I do like, I can bring it in.
Ug, now it sounds like PHP.
(Edited the first line a bit)