As it was brought up that my C hello world has little to do with C++, I'll go with some novice questions on that.

(Safe might be defined here as a way of writing code which avoids the bugs commonly associated with C or just "low risk of human error due to language design" as I don't know how C++ "safety" compares to C#)

Where does the safe C++ end and the C or unsafe concepts begin (as both can be in .cpp) - How can I tell which header has only C++ things in it (ignoring OS calls)? Are there things I can't do without use of C, eg. lack of libraries written this "safe/pure C++" that accomplish everything I could possibly want (in user land)?

Is there a C++ book/resource/authority that claims that by following their teaching you won't be making C-style mistakes or even that you get managed-level safety with C++ performance?