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

NAME
     std::front_insert_iterator - std::front_insert_iterator

Synopsis
	Defined in header <iterator>
	template< class Container >

	class						   front_insert_iterator
     (until C++17)

	    : public std::iterator<std::output_iterator_tag, void, void,
	void, void>
	template<		 class		      Container 	       >
     (since C++17)
	class front_insert_iterator;

	std::front_insert_iterator  is a LegacyOutputIterator that prepends ele-
     ments to a
	container for which it was  constructed.  The  container's  push_front()
     member function
	is  called  whenever  the  iterator (whether dereferenced or not) is as-
     signed to.
	Incrementing the std::front_insert_iterator is a no-op.

Member types
	Member type	  Definition
	iterator_category std::output_iterator_tag
	value_type	  void
	difference_type   void		 (until C++20)
			  std::ptrdiff_t (since C++20)
	pointer 	  void
	reference	  void
	container_type	  Container

	Member types iterator_category, value_type, difference_type, pointer
	and  reference	are  required  to  be  obtained   by   inheriting   from
     (until C++17)
	std::iterator<std::output_iterator_tag, void, void, void, void>.

Member functions
	constructor	constructs a new front_insert_iterator
			(public member function)
	operator=	inserts an object into the associated container
			(public member function)
	operator*	no-op
			(public member function)
	operator++	no-op
	operator++(int) (public member function)

Member objects
	Member name	      Definition
	container (protected) a pointer of type Container*

Example
     // Run this code

      #include <algorithm>
      #include <deque>
      #include <iostream>
      #include <iterator>
      #include <vector>

      namespace stb
      {
	  void println(auto, auto const& d)
	  {
	      std::ranges::copy(d, std::ostream_iterator<int>(std::cout, " "));
	      std::cout << '\n';
	  }
      }

      int main()
      {
	  std::vector<int> v{1, 2, 3, 4, 5};
	  std::deque<int> d;

	  std::copy(v.begin(), v.end(),
		    std::front_insert_iterator<std::deque<int>>(d));
		    // or std::front_inserter(d)

	  stb::println("{}", d);
      }

Output:
      5 4 3 2 1

See also
			     creates  a  std::front_insert_iterator  of type in-
     ferred from the
	front_inserter	     argument
			     (function template)
	back_insert_iterator iterator adaptor for insertion at the end of a con-
     tainer
			     (class template)
	insert_iterator      iterator adaptor for insertion into a container
			     (class template)

http://cppreference.com 	   2024.06.10	   std::front_insert_iterator(3)
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