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

NAME
     std::forward_iterator - std::forward_iterator

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

	    concept forward_iterator =
		std::input_iterator<I> &&
		std::derived_from</*ITER_CONCEPT*/<I>,
     (since C++20)
	std::forward_iterator_tag> &&
		std::incrementable<I> &&

		std::sentinel_for<I, I>;

	This concept refines std::input_iterator by requiring that I also model
	std::incrementable  (thereby  making  it  suitable  for multi-pass algo-
     rithms), and
	guaranteeing that two iterators  to  the  same	range  can  be	compared
     against each
	other.

Notes
	Unlike the LegacyForwardIterator requirements, the forward_iterator con-
     cept does not
	require dereference to return a reference.

Example
	A minimum forward iterator.

      #include <cstddef>
      #include <iterator>

      struct SimpleForwardIterator
      {
	  using difference_type = std::ptrdiff_t;
	  using value_type = int;

	  int operator*() const;

	  SimpleForwardIterator& operator++();

	  SimpleForwardIterator operator++(int)
	  {
	      auto tmp = *this;
	      ++*this;
	      return tmp;
	  }

	  bool operator==(const SimpleForwardIterator&) const;
      };

      static_assert(std::forward_iterator<SimpleForwardIterator>);

See also
			       specifies  that a type is an input iterator, that
     is, its
	input_iterator	       referenced values can be read and it can be  both
     pre- and
	(C++20) 	       post-incremented
			       (concept)
	bidirectional_iterator	specifies  that a forward_iterator is a bidirec-
     tional
	(C++20) 	       iterator, supporting movement backwards
			       (concept)

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