Is there a resource with a list of C ++ libraries and documentation, or how to find out what to use?

Question

C++ / C#

actually I read the self-instruction manual of 98 - already on the 70th page!!
there regularly appear new libraries in the examples, but I need to find out in advance because I'm doing tasks and add my requirements to them and I have to look for, for example, cstring or stdlib.h, fstream
where are the descriptions of the libraries?
So what else should I read?

Answer 1

www.cplusplus.com/reference