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

array whose contents to extract

Return value

A reference to the I^th element of a.

Complexity

Constant.

Example

#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

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) (C++11)	tuple accesses specified element (function template)
get(std::pair) (C++11)	accesses an element of a `pair` (function template)
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)
get(std::complex) (C++26)	obtains a reference to real or imaginary part from a `std::complex` (function template)