C++ Programming: Language Standard Headers

Standard Headers

Standard Template Library
algorithm array atomic bitset chrono codecvt complex condition_variable deque exception forward_list fstream functional future initializer_list iomanip ios	iosfwd iostream istream iterator limits list locale map memory mutex new numeric ostream queue random ratio regex set	sstream stack stdexcept streambuf string strstream system_error thread tuple type_traits typeinfo typeindex unordered_map unordered_set utility valarray vector

and the

Standard C Library
cassert ccomplex cctype cerrno cfenv cfloat cinttypes ciso646 climits	clocale cmath csetjmp csignal cstdalign cstdarg cstdbool cstddef cstdint	cstdio cstdlib cstring ctgmath ctime cuchar cwchar cwctype cwstring

Everything inside C++'s standard library is kept in the std:: namespace.

Old compilers may include headers with a .h suffix (e.g. the non-standard <iostream.h> vs. the standard <iostream>) instead of the standard headers. These names were common before the standardization of C++ and some compilers still include these headers for backwards compatibility. Rather than using the std:: namespace, these older headers pollute the global namespace and may otherwise only implement the standard in a limited way.

Some vendors use the SGI STL headers. This was the first implementation of the standard template library.

Non-standard but somewhat common C++ libraries
stdiostream.h	stream.h	strstream.h