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std::get(std::array)

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

array whose contents to extract

Return value

A reference to the I^th element of a.

Complexity

Constant.

Example

#include <array>
#include <iostream>
 
int main()
{
    std::array<int, 3> arr;
 
    // set values:
    std::get<0>(arr) = 1;
    std::get<1>(arr) = 2;
    std::get<2>(arr) = 3;
 
    // get values:
    std::cout << '(' << std::get<0>(arr)
              << ',' << std::get<1>(arr)
              << ',' << std::get<2>(arr)
              << ")\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

Structured binding (C++17)	binds the specified names to sub-objects or tuple elements of the initializer
operator[] (C++11)	access specified element (public member function)
at (C++11)	access specified element with bounds checking (public member function)
std::get(std::tuple) (C++11)	tuple accesses specified element (function template)
std::get(std::pair) (C++11)	accesses an element of a `pair` (function template)
std::get(std::variant) (C++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) (C++20)	obtains iterator or sentinel from a `std::ranges::subrange` (function template)