C style code has only one place, unsafe C++ coding for optimization purposes, only after validated through the use of a profiler.

In 99% of the applications it is usually irrelevant for what the users are expecting, and there are even some nice talks at Nokia Wrocław conferences, where the presenter was able to generate better compacter code with modern C++ instead of classical C code.

It was the C mentality brought into C++, back when learning C before C++ was the only path as C compilers were adding C++ support, that brought the daily CVEs we nowadays endure in such codebases.

"There is a place for old C style low level features, but those should come later, after the safer concepts are already ingrained."

And I agree that teaching idiomatic C++ is important and C stuff is an extension.

If replacing vector with a C array gives you 20-30% my general assumption is that vector was used wrongly and there were too many copies happening and passing a pointer around avoided them.

And yes, when teaching pure C++ students will also easily create too many copies, but that's better than all the buffer overflows, null pointer dereferences etc. happening to students of C. Such bugs cause frustration, but students need results which give satisfaction.

See the idea is you can use std::array, so you can use modern idioms (and at() for bounds checked access).

Also, the modern open source C++ stuff from Microsoft is also great.

Go for Chrome, V8, Dart, ChakraCore, the C++ part of DotNet VM.

But the only "problem" with them, is that they use their own sort of smart pointers, but if you know that they map 1-1 to smart pointers from std:: when you need to use the std ones, its not a big deal.

Chrome for instance have scoped_ptr = unique_ptr, scoped_refptr = shared_ptr, etc..