std::make_pair (3) - Linux Manuals

std::make_pair: std::make_pair

NAME

std::make_pair - std::make_pair

Synopsis

Defined in header <utility>
template< class T1, class T2 > (until C++11)
std::pair<T1,T2> make_pair( T1 t, T2 u );
template< class T1, class T2 > (since C++11)
std::pair<V1,V2> make_pair( T1&& t, T2&& u ); (until C++14)
template< class T1, class T2 > (since C++14)
constexpr std::pair<V1,V2> make_pair( T1&& t, T2&& u );

Creates a std::pair object, deducing the target type from the types of arguments.

The deduced types V1 and V2 are std::decay<T1>::type and std::decay<T2>::type (the usual type transformations applied to arguments of functions passed by value) unless application of std::decay results in std::reference_wrapper<X> for some type X, in which case the deduced type is X&. (since C++11)

Parameters

t, u - the values to construct the pair from

Return value

An std::pair object containing the given values.

Example

// Run this code

  #include <iostream>
  #include <utility>
  #include <functional>

  int main()
  {
      int n = 1;
      int a[5] = {1, 2, 3, 4, 5};

      // build a pair from two ints
      auto p1 = std::make_pair(n, a[1]);
      std::cout << "The value of p1 is "
                << "(" << p1.first << ", " << p1.second << ")\n";

      // build a pair from a reference to int and an array (decayed to pointer)
      auto p2 = std::make_pair(std::ref(n), a);
      n = 7;
      std::cout << "The value of p2 is "
                << "(" << p2.first << ", " << *(p2.second + 2) << ")\n";
  }

Output:

  The value of p1 is (1, 2)
  The value of p2 is (7, 3)