6. std::pair construction

• 
      std::pair< typename T, typename U >
  
  

• Default construction

• Construction from two items

• Construction from another pair (even with other types)

• The function make_pair( item1, item2 ) makes a pair.

  
      template< typename T, typename U >
      struct pair {
  
          pair();
  
          pair( T const& x, U const& y);
  
          template< typename V, typename W > pair( pair<V, W> const& pr);
      };