Standard library header <array>

C++

Language

Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

Standard Library header files

Language Support
<cstddef> <limits> <climits> <contract>	<cfloat> <cstdint> <new> <version>	<typeinfo> <exception> <initializer_list>	<csignal> <csetjmp> <cstdarg>
Concepts
<concepts>
Diagnostics
<stdexcept>	<cassert>	<cerrno>	<system_error>
General utilities
<utility> <memory> <memory_resource> <scoped_allocator> <compare>	<bitset> <tuple> <optional> <any> <variant>	<type_traits> <ratio> <chrono> <typeindex> <functional>	<ctime> <cstdlib>
Strings
<string> <string_view>	<cctype> <cwctype>	<cwchar> <cuchar>	<cstring> <charconv>
Localization
<locale>	<codecvt>	<clocale>
Containers
<span> <array> <vector>	<deque> <forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
Iterators
<iterator>
Algorithms
<algorithm>	<execution>
Numerics
<complex> <random>	<valarray> <numeric>	<cfenv> <cmath>	<bit>
Input/Output
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<sstream> <fstream> <syncstream>	<cstdio> <cinttypes> <strstream>
Regular expressions
<regex>
Filesystem support
<filesystem>
Thread support
<thread> <atomic>	<mutex> <shared_mutex>	<condition_variable> <future>
C compatibility
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

This header is part of the containers library.

Includes
<initializer_list>(C++11)
Classes
array (C++11)	static contiguous array (class template)
std::tuple_size<std::array>	obtains the size of an array (class template specialization)
std::tuple_element<std::array>	obtains the type of the elements of array (class template specialization)
Functions
operator==operator!=operator<operator<=operator>operator>=	lexicographically compares the values in the array (function template)
std::get(std::array)	accesses an element of an array (function template)
std::swap(std::array) (C++11)	specializes the std::swap algorithm (function template)

Synopsis

#include <initializer_list>

namespace std {

    template <class T, size_t N > struct array;

    template <class T, size_t N>
        bool operator==(const array<T,N>& x, const array<T,N>& y);
    template <class T, size_t N>
        bool operator!=(const array<T,N>& x, const array<T,N>& y);
    template <class T, size_t N>
        bool operator<(const array<T,N>& x, const array<T,N>& y);
    template <class T, size_t N>
        bool operator>(const array<T,N>& x, const array<T,N>& y);
    template <class T, size_t N>
        bool operator<=(const array<T,N>& x, const array<T,N>& y);
    template <class T, size_t N>
        bool operator>=(const array<T,N>& x, const array<T,N>& y);

    template <class T, size_t N >
        void swap(array<T,N>& x, array<T,N>& y) noexcept(noexcept(x.swap(y)));

    template <class T> class tuple_size;
    template <size_t I, class T> class tuple_element;
    template <class T, size_t N> struct tuple_size<array<T, N> >;
    template <size_t I, class T, size_t N> struct tuple_element<I, array<T, N> >;
    template <size_t I, class T, size_t N>
    constexpr T& get(array<T, N>&) noexcept;
    template <size_t I, class T, size_t N>
    constexpr T&& get(array<T, N>&&) noexcept;
    template <size_t I, class T, size_t N>
    constexpr const T& get(const array<T, N>&) noexcept;
    template <size_t I, class T, size_t N>
    constexpr const T&& get(const array<T, N>&&) noexcept;
}

Class std::array

template <class T, size_t N >
struct array {
    // types:
    typedef T&                               reference;
    typedef const T&                         const_reference;
    typedef /*implementation-defined*/       iterator;
    typedef /*implementation-defined*/       const_iterator;
    typedef size_t                           size_type;
    typedef ptrdiff_t                        difference_type;
    typedef T                                value_type;
    typedef T*                               pointer;
    typedef const T*                         const_pointer;
    typedef reverse_iterator<iterator>       reverse_iterator;
    typedef reverse_iterator<const_iterator> const_reverse_iterator;

    T elems[N]; // exposition only

    // no explicit construct/copy/destroy for aggregate type

    void fill(const T& u);
    void swap(array<T, N>&) noexcept(is_nothrow_swappable_v<T>);

    // iterators:
    constexpr iterator                begin() noexcept;
    constexpr const_iterator          begin() const noexcept;
    constexpr iterator                end() noexcept;
    constexpr const_iterator          end() const noexcept;

    constexpr reverse_iterator        rbegin() noexcept;
    constexpr const_reverse_iterator  rbegin() const noexcept;
    constexpr reverse_iterator        rend() noexcept;
    constexpr const_reverse_iterator  rend() const noexcept;

    constexpr const_iterator          cbegin() const noexcept;
    constexpr const_iterator          cend() const noexcept;
    constexpr const_reverse_iterator  crbegin() const noexcept;
    constexpr const_reverse_iterator  crend() const noexcept;

    // capacity:
    constexpr size_type size() const noexcept;
    constexpr size_type max_size() const noexcept;
    constexpr bool      empty() const noexcept;

    // element access:
    constexpr reference       operator[](size_type n);
    constexpr const_reference operator[](size_type n) const;
    constexpr const_reference at(size_type n) const;
    constexpr reference       at(size_type n);
    constexpr reference       front();
    constexpr const_reference front() const;
    constexpr reference       back();
    constexpr const_reference back() const;

    constexpr T *       data() noexcept;
    constexpr const T * data() const noexcept;
};

template<class T, class... U>
  array(T, U...) -> array<T, 1 + sizeof...(U)>;

Note

The variable array::elems is only for exposition, it's not part of the interface.