I have done low-level and mobile programming on very restricted platforms and I cannot see any reason why in the world I would use C instead of C++. Basically there is always an opportunity to use C++ if you can use C. Myths that C++ is slower are spread by people who just do not know C++ well or are not skilled/clever enough to use it.
Indeed. And there are numerous reasons why C++ code can be/is significantly faster; firstly code inlining for code that would be required to use function pointers in C (ala qsort vs std::sort), secondly, things such as expression templates for things such as Matrix libraries.
