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std::multiset::multiset(3)    C++ Standard Libary   std::multiset::multiset(3)

NAME
       std::multiset::multiset - std::multiset::multiset

Synopsis
	  multiset();						     (1)
	  explicit multiset( const Compare& comp,		     (2)
	  const	Allocator& alloc = Allocator() );
	  explicit  multiset(  const  Allocator&  alloc	 );		   (3)
       (since C++11)
	  template< class InputIt >

	  multiset( InputIt first, InputIt last,		     (4)
	  const	Compare& comp =	Compare(),

	  const	Allocator& alloc = Allocator() );
	  template< class InputIt >

	  multiset(  InputIt  first,  InputIt  last,			   (5)
       (since C++14)

	  const	Allocator& alloc );
	  multiset( const multiset& other );			     (6)
	  multiset(  const  multiset&  other,  const  Allocator&  alloc	); (7)
       (since C++11)
	  multiset(  multiset&&	 other	 );				   (8)
       (since C++11)
	  multiset(  multiset&&	 other,	 const	Allocator&  alloc  );	   (9)
       (since C++11)
	  multiset( std::initializer_list<value_type> init,

	  const	 Compare&  comp	 =  Compare(),				  (10)
       (since C++11)

	  const	Allocator& alloc = Allocator() );
	  multiset(   std::initializer_list<value_type>	  init,		  (11)
       (since C++14)
	  const	Allocator& );

	  Constructs new container from	a variety of data sources and  option-
       ally using user
	  supplied allocator alloc or comparison function object comp.

	  1-3) Constructs an empty container.
	  4-5) Constructs the container	with the contents of the range [first,
       last).
	  6-7) Copy constructor. Constructs the	container with the copy	of the
       contents	of
	  other.

	  If   alloc  is  not  provided,  allocator  is	 obtained  by  calling
       (since
	  std::allocator_traits<allocator_type>::select_on_container_copy_con-
       struction( C++11)
	  other.get_allocator()).
	  The template parameter Allocator is only deduced from	the first  ar-
       gument	   (since
	  while	    used     in	   class    template	argument    deduction.
       C++23)

	  8-9) Move constructor. Constructs the	container with the contents of
       other using
	  move semantics. If alloc is not provided, allocator is  obtained  by
       move-construction
	  from the allocator belonging to other.

	  The  template	 parameter  Allocator  is  only	deduced	from the first
       (since C++23)
	  argument while used in class template	argument deduction.

	  10-11) Constructs the	container with the contents of the initializer
       list init.

Parameters
	  alloc	      -	allocator to use for all memory	 allocations  of  this
       container
	  comp	       - comparison function object to use for all comparisons
       of keys
	  first, last -	the range to copy the elements from
	  other	      -	another	container to be	used as	source	to  initialize
       the elements of
			the container with
	  init	       -  initializer  list  to	initialize the elements	of the
       container with

Type requirements
	  -
	  InputIt must meet the	requirements of	LegacyInputIterator.
	  -
	  Compare must meet the	requirements of	Compare.
	  -
	  Allocator must meet the requirements of Allocator.

Complexity
	  1-3) Constant
	  4-5) N log(N)	where N	= std::distance(first, last) in	general,  lin-
       ear in N	if the
	  range	is already sorted by value_comp().
	  6-7) Linear in size of other
	  8-9) Constant. If alloc is given and alloc !=	other.get_allocator(),
       then linear.
	  10-11)  N  log(N)  where  N =	init.size() in general,	linear in N if
       init is already
	  sorted by value_comp().

Exceptions
	  Calls	to Allocator::allocate may throw.

Notes
	  After	container  move	 construction  (overload  (8-9)),  references,
       pointers, and
	  iterators  (other  than the end iterator) to other remain valid, but
       refer to	elements
	  that are now in *this. The current standard makes this guarantee via
       the blanket
	  statement in [container.requirements.general]/12, and	a more	direct
       guarantee is
	  under	consideration via LWG 2321.

	  Although not formally	required until C++23, some implementations has
       already put the
	  template  parameter  Allocator  into non-deduced contexts in earlier
       modes.

Example
       // Run this code

	#include <iostream>
	#include <string_view>
	#include <set>

	void print(const std::string_view name,	const std::multiset<int>& ms)
	{
		std::cout << name << ":	";
		for(auto element: ms)
			std::cout << element <<	" ";
		std::cout << '\n';
	}

	int main()
	{
		// (1) Default constructor
		std::multiset<int> a;
		a.insert(4);
		a.insert(3);
		a.insert(2);
		a.insert(1);
		print("a", a);

		// (4) Iterator	constructor
		std::multiset<int> b(a.begin(),	a.find(3));
		print("b", b);

		// (6) Copy constructor
		std::multiset<int> c(a);
		print("c", c);

		// (8) Move constructor
		std::multiset<int> d(std::move(a));
		print("d", d);

		// (10)	Initializer list constructor
		std::multiset<int> e {3,2,1,2,4,7,3};
		print("e", e);
	}

Output:
	a: 1 2 3 4
	b: 1 2
	c: 1 2 3 4
	d: 1 2 3 4
	e: 1 2 2 3 3 4 7

	 Defect	reports

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

	     DR	   Applied to	     Behavior as published	  Correct  be-
       havior
	  LWG 2193 C++11      the default constructor is explicit made non-ex-
       plicit

See also
	  operator= assigns values to the container
		    (public member function)

http://cppreference.com		  2022.07.31	    std::multiset::multiset(3)

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