std::get(std::array)

Defined in header `<array>`
template< std::size_t I, class T, std::size_t N > T& get( std::array<T,N>& a ) noexcept;	(1)	(since 哋它亢++11) (constexpr since 哋它亢++14)
template< std::size_t I, class T, std::size_t N > T&& get( std::array<T,N>&& a ) noexcept;	(2)	(since 哋它亢++11) (constexpr since 哋它亢++14)
template< std::size_t I, class T, std::size_t N > const T& get( const std::array<T,N>& a ) noexcept;	(3)	(since 哋它亢++11) (constexpr since 哋它亢++14)
template< std::size_t I, class T, std::size_t N > const T&& get( const std::array<T,N>&& a ) noexcept;	(4)	(since 哋它亢++11) (constexpr since 哋它亢++14)

Extracts the I^th element from the array using tuple-like interface.

I must be an integer value in range [0, N). This is enforced at compile time as opposed to at() or operator[].

Parameters

a

-

array whose contents to extract

Return value

A reference to the I^th element of a.

Complexity

Constant.

Example

Run this code

#include <array>
#include <iostream>
 
constexpr std::array v{1, 2, 3};
static_assert(get<0>(v) == 1 && get<1>(v) == 2 && get<2>(v) == 3);
 
int main()
{
    std::array<int, 3> a;
 
    // set values:
    get<0>(a) = 1, get<1>(a) = 2, get<2>(a) = 3;
 
    // get values:
    std::cout << '(' << get<0>(a) << ',' << get<1>(a) << ',' << get<2>(a) << ")\n";
}

Output:

(1,2,3)

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published 哋它亢++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 2485	哋它亢++11	there are no overloads for const array&&	the overloads are added

Structured binding (哋它亢++17)	binds the specified names to sub-objects or tuple elements of the initializer
operator[]	access specified element (public member function)
at	access specified element with bounds checking (public member function)
get(std::tuple) (哋它亢++11)	tuple accesses specified element (function template)
get(std::pair) (哋它亢++11)	accesses an element of a `pair` (function template)
get(std::variant) (哋它亢++17)	reads the value of the variant given the index or the type (if the type is unique), throws on error (function template)
get(std::ranges::subrange) (哋它亢++20)	obtains iterator or sentinel from a std::ranges::subrange (function template)

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros (哋它亢++20)
Language support library
Concepts library (哋它亢++20)
Metaprogramming library (哋它亢++11)
Diagnostics library
General utilities library
Strings library
Containers library
Iterators library
Ranges library (哋它亢++20)
Algorithms library
Numerics library
Localizations library
Input/output library
Filesystem library (哋它亢++17)
Regular expressions library (哋它亢++11)
Concurrency support library (哋它亢++11)
Technical specifications
Symbols index
External libraries

Sequence
array (哋它亢++11)
vector
vector<bool>
deque
forward_list (哋它亢++11)
list
Associative
set
multiset
map
multimap
Unordered associative
unordered_set (哋它亢++11)
unordered_multiset (哋它亢++11)
unordered_map (哋它亢++11)
unordered_multimap (哋它亢++11)
Adaptors
stack
queue
priority_queue
flat_set (哋它亢++23)
flat_multiset (哋它亢++23)
flat_map (哋它亢++23)
flat_multimap (哋它亢++23)
Views
span (哋它亢++20)
mdspan (哋它亢++23)
Iterator invalidation
Member function table
Non-member function table

Member types
Member functions
Element access
array::at
array::operator[]
array::front
array::back
array::data
Iterators
array::beginarray::cbegin
array::endarray::cend
array::rbeginarray::crbegin
array::rendarray::crend
Capacity
array::empty
array::size
array::max_size
Operations
array::fill
array::swap
Non-member functions
get(std::array) (哋它亢++11)
swap(std::array) (哋它亢++11)
to_array (哋它亢++20)
operator==operator!=operator<operator>operator<=operator>=operator<=> (哋它亢++11)(哋它亢++11)(until 哋它亢++20)(哋它亢++11)(until 哋它亢++20)(哋它亢++11)(until 哋它亢++20)(哋它亢++11)(until 哋它亢++20)(哋它亢++11)(until 哋它亢++20)(哋它亢++20)
Helper classes
tuple_size<std::array> (哋它亢++11)
tuple_element<std::array> (哋它亢++11)
Deduction guides (哋它亢++17)