std::get(std::pair) (3) - Linux Manuals

std::get(std::pair): std::get(std::pair)

NAME

std::get(std::pair) - std::get(std::pair)

Synopsis

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

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

p - 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

// Run this code

  #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)