This is not a question about which of the two languages is better than the other. I myself can't really decide. Pros and cons as always I guess.

Also, if you feel you always would prefer C over C++, this poll is not for you :-).

However, when I work in C projects I usually feel I'm missing a few language constructs more than others, which can be found in C++.

For example, I usually miss (the obvious) classes, but seldomly templates (I always miss STL, but wouldn't call it a language construct).

What do you miss when you have to use C instead of C++?