std::experimental::ranges::ForwardIterator(3)

NAME
std::experimental::ranges::ForwardIterator - std::experimental::ranges::ForwardIterator

Synopsis
   Defined in header <experimental/ranges/iterator>
   template < class I >
   concept bool ForwardIterator =
   InputIterator<I> &&
   DerivedFrom<ranges::iterator_category_t<I>, (ranges TS)
   ranges::forward_iterator_tag> &&
   Incrementable<I> &&
   Sentinel<I, I>;
   The concept ForwardIterator<I> refines InputIterator by adding equality comparison
   and the multi-pass guarantee.
   The domain of == for forward iterators is that of iterators over the same underlying
   sequence, except that value-initialized iterators of the same type may be compared
   with each other and shall compare equal.
   Pointers and references obtained from a forward iterator into a range [i, s) must
   remain valid while [i, s) continues to denote a range.
   Let a and b be two deferenceable iterators of type I. ForwardIterator<I> is
   satisfied only if:
     * a == b implies ++a == ++b; and
     * The expression ([](X x){++x;}(a), *a) is equivalent to *a, i.e., incrementing a
       copy of a has no effect on the result of dereferencing a.
   This is known as the multi-pass guarantee.

Notes
   A forward iterator cannot be "stashing": it cannot return a reference to an object
   within itself, because such references would be invalidated by the destruction of
   the forward iterator.