You mean about variable types? Basically C++ is (almost) a perfect superset of C so almost all your C known issues work on C++.
C++ on the other hand provide some new types. I don't refer to user-defined ones as they are infinite of course. bool is not supported in C, you have to use int, short etc. I think it was added after as _Bool.
Anyway short, int, long, float, double all exist in both.
Also there is no std::string, vector etc. For strings in C it's always char * and char[N]