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std::get(std::pair)

Defined in header `<utility>`
	(1)
template< size_t I, class T1, class T2 > typename std::tuple_element<I, std::pair<T1,T2> >::type& get( pair<T1, T2>& p ) noexcept;		(since C++11) (until C++14)
template< size_t I, class T1, class T2 > constexpr std::tuple_element_t<I, std::pair<T1,T2> >& get( pair<T1, T2>& p ) noexcept;		(since C++14)
	(2)
template< size_t I, class T1, class T2 > const typename std::tuple_element<I, std::pair<T1,T2> >::type& get( const pair<T1,T2>& p ) noexcept;		(since C++11) (until C++14)
template< size_t I, class T1, class T2 > constexpr const std::tuple_element_t<I, std::pair<T1,T2> >& get( const pair<T1,T2>& p ) noexcept;		(since C++14)
	(3)
template< size_t I, class T1, class T2 > typename std::tuple_element<I, std::pair<T1,T2> >::type&& get( std::pair<T1,T2>&& p ) noexcept;		(since C++11) (until C++14)
template< size_t I, class T1, class T2 > constexpr std::tuple_element_t<I, std::pair<T1,T2> >&& get( std::pair<T1,T2>&& p ) noexcept;		(since C++14)
template< size_t I, class T1, class T2 > constexpr const std::tuple_element_t<I, std::pair<T1,T2> >&& get( const std::pair<T1,T2>&& p ) noexcept;	(4)	(since C++17)
template <class T, class U> constexpr T& get(std::pair<T, U>& p) noexcept;	(5)	(since C++14)
template <class T, class U> constexpr const T& get(const std::pair<T, U>& p) noexcept;	(6)	(since C++14)
template <class T, class U> constexpr T&& get(std::pair<T, U>&& p) noexcept;	(7)	(since C++14)
template <class T, class U> constexpr const T&& get(const std::pair<T, U>&& p) noexcept;	(8)	(since C++17)
template <class T, class U> constexpr T& get(std::pair<U, T>& p) noexcept;	(9)	(since C++14)
template <class T, class U> constexpr const T& get(const std::pair<U, T>& p) noexcept;	(10)	(since C++14)
template <class T, class U> constexpr T&& get(std::pair<U, T>&& p) noexcept;	(11)	(since C++14)
template <class T, class U> constexpr const T&& get(const std::pair<U, T>&& p) noexcept;	(12)	(since C++17)

Extracts an element from the pair using tuple-like interface.

The index-based overloads (1-4) fail to compile if the index I is neither 0 nor 1.

The type-based overloads (5-12) fail to compile if the types T and U are the same.

Parameters

pair whose contents to extract

Return value

1-4) Returns a reference to p.first if I==0 and a reference to p.second if I==1.

5-8) Returns a reference to p.first.

9-12) Returns a reference to p.second.

Example

#include <iostream>
#include <utility>
 
int main()
{
    auto p = std::make_pair(1, 3.14);
    std::cout << '(' << std::get<0>(p) << ", " << std::get<1>(p) << ")\n";
    std::cout << '(' << std::get<int>(p) << ", " << std::get<double>(p) << ")\n";
}

Output:

(1, 3.14)
(1, 3.14)

std::get(std::tuple)	tuple accesses specified element (function template)
std::get(std::array)	accesses an element of an `array` (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)

std::get(std::pair)

Parameters

Return value

Example

See also