std::get(std::array)

From cppreference.com
< cpp‎ | container‎ | 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 Ith element from the array using tuple-like interface.

I must be an integer value in range [0N). 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 Ith 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

See also

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