std::make_pair(3)

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 ); (constexpr since C++14)
   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 (since C++11)
   std::decay results in std::reference_wrapper<X> for some type X, in
   which case the deduced type is X&.

Parameters
   t, u - the values to construct the pair from

Return value
   A std::pair object containing the given values.

Example
// Run this code
 #include <functional>
 #include <iostream>
 #include <utility>
 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)
   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 181 C++98 the parameter types were const-reference changed these
                      types, which made passing arrays impossible types to value types