<cmath>

Math functions, such as exp() , sqrt() , log() , abs() , all trigonometric functions, and more.

<cstdint>

A set of typedef s for integral types with certain width requirements: for example, int32_t and int_fast64_t .

<limits>

numeric_limits , offering properties—such as min() , max() , lowest() , infinity() , quiet_NaN() , and so on—for all built-in arithmetic types.

<climits>

Macros for C-style limits of integral types, such as INT_MAX . Subsumed by <limits> .

<cfloat>

Macros to describe details of the floating-point types of your environment, e.g. FLT_EPSILON , FLT_MAX , and so on. Subsumed by <limits> .

<cfenv>

Advanced access to the floating-point environment to configure floating-point exceptions, rounding, and other environment settings.

<complex>

The complex class for working with complex numbers.

<ccomplex>

Simply includes <complex> .

<ctgmath>

Includes <cmath> and <ccomplex> .

<ratio>

The ratio template, helper templates for performing arithmetic operations and comparisons on them, and a set of predefined ratio s.

<random>

Pseudo-random number generators, random_device , and various random number distributions.

<valarray>

valarray functionality for working with arrays of numeric values.

<utility>

pair and piecewise_construct . Functions make_pair() , swap() , forward() , move() , move_if_noexcept() , and declval() .

<tuple>

tuple , helper classes tuple_size and tuple_element , and functions make_tuple() , forward_as_tuple() , tie() , tuple_cat() , and get() .

<memory>

Smart pointers: unique_ptr , shared_ptr , and weak_ptr . Default allocators.

<new>

Functions for managing dynamic storage: operators new , new[] , delete , and delete[] , get_ and set_new_handler() , and exceptions bad_alloc and bad_array_new_length .

<functional>

Reference wrappers (created with ref() / cref() ), predefined functors (function objects), functor negators, std::function , bind() , and mem_fn() .

<initializer_list>

The definition of initializer_list .

<chrono>

Time utilities: duration s, time_point s, and clocks ( steady_clock , system_clock , and high_resolution_clock ).

<ctime>

C-style time and date utilities such as the tm struct , time() , localtime() , and strftime() .

<cstdio>

C-style file utilities: remove() , rename() , tmpfile() , and tmpnam() . Also provides C-style stream I/O functionality: see Chapter 5 .

<typeinfo>

type_info , and the exceptions bad_cast and bad_typeid .

<typeindex>

type_index , a wrapper for type_info to be able to use it as a key in associative containers.

<type_traits>

Template-based type traits for compile-time manipulation and inspection of properties of types.

<iterator>

Functions to perform operations on iterators: advance() , distance() , begin() , end() , prev() , and next() , and the iterator tags. Chapter 4 discusses input/output iterators and the predefined iterator adaptors: reverse_iterator , move_iterator , and insert iterators. Stream iterators are discussed in Chapter 5 .

<vector>

The vector class template and the vector<bool> specialization.

<deque>

The deque class template.

<array>

The array class template.

<list>

The list class template.

<forward_list>

The forward_list class template.

<bitset>

The bitset class template.

<queue>

The queue and priority_queue class templates.

<stack>

The stack class template.

<map>

The map and multimap class templates.

<set>

The set and multiset class templates.

<unordered_map>

The unordered_map and unordered_multimap class templates.

<unordered_set>

The unordered_set and unordered_multiset class templates.

<algorithm>

All available algorithms, except those that are in <numeric> .

<numeric>

Numerical algorithms: accumulate() , adjacent_difference() , inner_product() , partial_sum() , and iota() .

<ios>

ios_base , basic_ios , and fpos , typedef s ios and wios , and types streamoff , streampos , wstreampos , and streamsize . Non-parametric I/O manipulators such as boolalpha , dec , scientific , and so on.

<iomanip>

Parametric I/O manipulators such as setbase() , setfill() , get_money() , put_time() , and more.

<ostream>

basic_ostream , and typedef s ostream and wostream . The endl , ends , and flush output manipulators.

<istream>

basic_istream and basic_iostream , and typedef s istream , wistream , iostream , and wiostream . The ws input manipulator.

<iostream>

cin / wcin , cout / wcout , cerr / wcerr , and clog / wclog . Includes <ios> , <streambuf> , <istream> , <ostream> , and <iosfwd> .

<sstream>

String streams: basic_istringstream , basic_ostringstream , basic_stringstream , basic_stringbuf , and related typedef s.

<fstream>

File streams: basic_ifstream , basic_ofstream , basic_fstream , and basic_filebuf , and related typedef s.

<streambuf>

basic_streambuf , and typedef s streambuf and wstreambuf .

<iosfwd>

Forward declarations for all stream I/O types.

<cstdio>

The C-style I/O library. Basic file utilities (see Chapter 2 ) , plus fopen() , fclose() , and so on. Functions for formatted ( printf() , scanf() , and so on ) and character-based I/O ( getc() , putc() , and so on ). It is generally recommended that you use C++ I/O streams.

<cinttypes>

Macros to use with printf() and scanf() to handle the fixed-width integer types of <cstdint> . Subsumed by C++ I/O streams.

<strstream>

Deprecated.

<string>

basic_string , and typedef s string , wstring , u16string , and u32string . Conversion functions such as stoi() , stof() , to_string() , and so on.

<cstring>

Low-level memory functions: memcpy() , memmove() , memcmp() , memchr() , and memset() . A collection of C-style string functions, e.g. strcpy() and strcat() , and a definition for NULL and size_t .

<cwchar>

Functions to work with C-style wide character strings, such as fputws() , wprintf() , wcstof() , wcscat() , wmemset() , and so on.

<cctype>

Functions to classify and transform characters: isdigit() , isspace() , tolower() , toupper() , and so on.

<cwctype>

Wide character versions of functions from <cctype> : iswdigit() , iswspace() , towlower() , towupper() , and so on.

<codecvt>

Unicode character encoding conversion facets: codecvt_utf8 , codecvt_utf16 , and codecvt_utf8_utf16 .

<cuchar>

Functions to convert between 16 or 32-bit character and multibyte sequences: c16rtomb() , c32rtomb() , mbrtoc16() , and mbrtoc32() .

<locale>

The locale class, overloads of <cctype> functions accepting a given locale , facet functions use_facet() and has_facet() , and standard facet classes num_get , collate , money_put , codecvt , and so on.

<clocale>

lconv and the setlocale() and localeconv() functions. setlocale() only changes the C locale.

<regex>

Everything related to regular expressions.

<thread>

The thread class and the this_thread namespace.

<future>

future and shared_future , future_error , and providers promise , packaged_task , and async() .

<mutex>

mutex , recursive_mutex , timed_mutex , recursive_timed_mutex , lock_guard , unique_lock , and related types. Functions try_lock() , lock() , and call_once() .

<shared_mutex>

shared_mutex , shared_timed_mutex , and shared_lock .

<condition_variable>

condition_variable and condition_variable_any , and the function notify_all_at_thread_exit() .

<atomic>

Atomic types and fences.

<cassert>

The assert() macro.

<exception>

exception and bad_exception , exception pointers, nested exceptions, terminate, and unexpected handlers.

<stdexcept>

Exception classes for reporting common errors: logic_error , runtime_error , and their generic subclasses.

<system_error>

The std::system_error exception used to report low-level errors, and the concepts of error codes, conditions, and categories.

<cerrno>

The errno expression and default error-condition values.

<ciso646>

Only useful for C. Defines macros such as and , or , not , and so on. In C++, those are reserved words, so this header is empty.

<csetjmp>

longjmp() and setjmp() . Do not use these in C++.

<csignal>

signal() and raise() . Do not use these in C++.

<cstdalign>

The __alignas_is_defined macro: always expands to 1 for C++.

<cstdarg>

The va_list type and functions va_start() , va_arg() , va_end() , and va_copy() to handle variable-length argument lists. In C++, it is recommended that you use type-safe variadic templates instead.

<cstdbool>

The __bool_true_false_are_defined macro: expands to 1 for C++.

<cstddef>

Types ptrdiff_t , size_t , max_align_t , and nullptr_t . The macro offsetof() and the constant NULL .

<cstdlib>

String conversion functions: atof() , strtof() , and so on.

Multibyte character functions: mblen() , mbtowc() , and wctomb() .

Multibyte string conversion: mbstowcs() and wcstombs() .

Searching and sorting: bsearch() and qsort() (use <algorithm> ).

Random numbers: rand() and srand() (deprecated; use <random> ).

Memory management: calloc() , free() , malloc() , and realloc() .

Integer functions: abs() , div( ), labs() , ldiv() , llabs() , and lldiv() .

Functions abort() , atexit() , at_quick_exit() , exit() , getenv() , quick_exit() , system() , and _Exit() .