Standard C++ Library Overview
All C++ library entities are declared or defined in one or more standard headers. To make use of a library entity in a program, write an include directive that names the relevant standard header. The Standard C++ Library consists of 50 required headers. This implementation also includes two additional headers, <hash_map> and <hash_set>, that are not required by the C++ Standard, for a total of 52 headers. These 52 C++ library headers (with the additional 18 Standard C headers) constitute a hosted implementation of the C++ library.
A freestanding implementation of the C++ library provides only a subset of these headers:
<cstdlib> (declaring at least the functions abort, atexit, and exit)
The C++ library headers have two broader subdivisions:
This section contains the following sections:
For more information about Visual C++ run-time libraries, see C Run-Time Libraries.