C Library. The C++ library includes the same definitions as the C language library organized in the same structure of header files, with the following differences:Each header file has the same name as the C language version but with a "c" prefix and no extension.
For example, the C++ equivalent for the C language header file <stdlib.h> is <cstdlib>.Every element of the library is defined within the std namespace. Nevertheless, for compatibility with C, the traditional header names name.h (like stdlib.h) are also provided with the same definitions within the global namespace. In the examples provided in this reference, this version is used so that the examples are fully C-compatible, although its use is deprecated in C++.
The are also certain specific changes in the C++ implementation: Reference. Search: Reference Not logged in Reference Standard C++ Library reference C Library. C programming.com - Learn C and C++ Programming.