NAME¶

std::get(std::array) - std::get(std::array)

Synopsis¶

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

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

See also¶

Structured binding (C++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) tuple accesses specified element
(C++11) (function template)
get(std::pair) accesses an element of a pair
(C++11) (function template)
get(std::variant) reads the value of the variant given the index or the
(C++17) type (if the type is unique), throws on error
(function template)
get(std::ranges::subrange) obtains iterator or sentinel from a std::ranges::subrange
(C++20) (function template)