home | help 
std::multimap::insert(3)       C++ Standard Libary	std::multimap::insert(3)

NAME
     std::multimap::insert - std::multimap::insert

Synopsis
	iterator insert( const value_type& value );	     (1)
	iterator insert( value_type&& value );		     (2) (since C++17)
	template< class P >				     (3) (since C++11)
	iterator insert( P&& value );
	iterator      insert(	   iterator	 pos,	   const     value_type&
     (until C++11)
	value );
	iterator	insert(        const_iterator	      pos,	   const
     (since C++11)
	value_type& value );
	iterator    insert(    const_iterator	pos,   value_type&&	     (5)
     (since C++17)
	value );
	template<    class    P    >					     (6)
     (since C++11)
	iterator insert( const_iterator pos, P&& value );    (4)
	template< class InputIt >				 (7)
	void insert( InputIt first, InputIt last );
	void	insert(    std::initializer_list<value_type>	ilist	     (8)
     (since C++11)
	);
	iterator   insert(   node_type&&   nh	 );			     (9)
     (since C++17)
	iterator   insert(   const_iterator   pos,   node_type&&   nh	    (10)
     (since C++17)
	);

	Inserts element(s) into the container.

	1-3) Inserts value. If the container has elements with	equivalent  key,
     inserts at
	the upper bound of that range.
	Overload  (3)  is equivalent to emplace(std::forward<P>(value)) and only
     participates
	in overload resolution if std::is_constructible<value_type,  P&&>::value
     == true.
	4-6)  Inserts value in the position as close as possible to the position
     just prior
	to pos.
	Overload (6) is equivalent to emplace_hint(hint, std::forward<P>(value))
     and only
	participates in overload resolution if std::is_constructible<value_type,
     P&&>::value
	== true.
	7) Inserts elements from range [first, last).
	8) Inserts elements from initializer list ilist.
	9) If nh is an empty node handle, does nothing. Otherwise,  inserts  the
     element owned
	by  nh	into  the  container and returns an iterator pointing at the in-
     serted element.
	If a range containing elements with keys equivalent to	nh.key()  exists
     in the
	container,  the element is inserted at the end of that range. The behav-
     ior is
	undefined if nh is not empty and get_allocator() != nh.get_allocator().
	10) If nh is an empty node handle, does nothing and returns the end  it-
     erator.
	Otherwise,  inserts  the element owned by nh into the container, and re-
     turns the
	iterator pointing to the element with key equivalent  to  nh.key().  The
     element is
	inserted as close as possible to the position just prior to pos. The be-
     havior is
	undefined if nh is not empty and get_allocator() != nh.get_allocator().

	No iterators or references are invalidated.
	If  the  insertion is successful, pointers and references to the element
     obtained
	while it is held in the node handle are invalidated,  and  pointers  and
     references
	obtained to that element before it was extracted become valid.
	(since C++17)

Parameters
	pos	    - iterator to the position before which the new element will
     be inserted
	value	    - element value to insert
	first, last - range of elements to insert
	ilist	    - initializer list to insert the values from
	nh	    - a compatible node handle

Type requirements
	-
	InputIt must meet the requirements of LegacyInputIterator.

Return value
	1-6) An iterator to the inserted element.
	7,8) (none)
	9,10)  End  iterator  if nh was empty, iterator pointing to the inserted
     element
	otherwise.

Exceptions
	1-6) If an exception is thrown by any operation, the  insertion  has  no
     effect.
	7,8) No exception safety guarantee.
	9,10)  If  an exception is thrown by any operation, the insertion has no
     effect.

Complexity
	1-3) O(log(size()))
	4-6) Amortized constant if the insertion happens in  the  position  just
     before pos,
	O(log(size())) otherwise.
	7,8) O(NA.log(size() + N)), where N is the number of elements to insert.
	9) O(log(size()))
	10) Amortized constant if the insertion happens in the position just be-
     fore pos,
	O(log(size())) otherwise.

Example
     // Run this code

      #include <functional>
      #include <iostream>
      #include <map>
      #include <string>
      #include <string_view>
      #include <utility>

      template<class M>
      void print(const std::string_view rem, const M& mmap)
      {
	  std::cout << rem << ' ';
	  for (const auto& e : mmap)
	      std::cout << '{' << e.first << ',' << e.second << "} ";
	  std::cout << '\n';
      }

      int main()
      {
	  // list-initialize
	  std::multimap<int, std::string, std::greater<int>> mmap
	      {{2, "foo"}, {2, "bar"}, {3, "baz"}, {1, "abc"}, {5, "def"}};
	  print("#1", mmap);

	  // insert using value_type
	  mmap.insert(decltype(mmap)::value_type(5, "pqr"));
	  print("#2", mmap);

	  // insert using pair
	  mmap.insert(std::pair{6, "uvw"});
	  print("#3", mmap);

	  mmap.insert({7, "xyz"});
	  print("#4", mmap);

	  // insert using initializer_list
	  mmap.insert({{5, "one"}, {5, "two"}});
	  print("#5", mmap);

	  // insert using a pair of iterators
	  mmap.clear();
	  const  auto  il  = {std::pair{1, "Ax"}, {2, "N"}, {2, "A<paragraph>"},
     {3, "A1/4"}};
	  mmap.insert(il.begin(), il.end());
	  print("#6", mmap);
      }

Output:
      #1 {5,def} {3,baz} {2,foo} {2,bar} {1,abc}
      #2 {5,def} {5,pqr} {3,baz} {2,foo} {2,bar} {1,abc}
      #3 {6,uvw} {5,def} {5,pqr} {3,baz} {2,foo} {2,bar} {1,abc}
      #4 {7,xyz} {6,uvw} {5,def} {5,pqr} {3,baz} {2,foo} {2,bar} {1,abc}
      #5 {7,xyz} {6,uvw} {5,def} {5,pqr} {5,one} {5,two} {3,baz} {2,foo} {2,bar}
     {1,abc}
      #6 {3,A1/4} {2,N} {2,A<paragraph>} {1,Ax}

	Defect reports

	The following behavior-changing defect	reports  were  applied	retroac-
     tively to
	previously published C++ standards.

	   DR	  Applied  to	      Behavior as published		 Correct
     behavior
								  the  insertion
     is required
			    pos was just a hint, it could be	  to
	LWG 233  C++98	    totally ignored			  be as close as
     possible to
								  the
								  position  just
     prior to pos
			    the complexity of overload (5)  was     removed  the
     linear
	LWG 264  C++98	    required to be linear if		  requirement
			    the  range	[first, last) is sorted     in this spe-
     cial case
			    according to Compare
	LWG 371  C++98	    the order of equivalent elements	  required to be
     preserved
			    was not guaranteed to be preserved
	LWG 2005 C++11	    overloads (3,6) were poorly described  improved  the
     description

See also
	emplace      constructs element in-place
	(C++11)      (public member function)
	emplace_hint constructs elements in-place using a hint
	(C++11)      (public member function)
	inserter      creates  a  std::insert_iterator of type inferred from the
     argument
		     (function template)

http://cppreference.com 	   2024.06.10		std::multimap::insert(3)
home | help