std::ranges::concat_view<Views...>::iterator - cppreference.com (original) (raw)

template< bool Const > class /iterator/	(1)	(exposition only*)
Helper concepts
template< bool Const, class... Rs >concept /concat-is-random-access/ = /* see description */;	(2)	(exposition only*)
template< bool Const, class... Rs >concept /concat-is-bidirectional/ = /* see description */;	(3)	(exposition only*)

Let Fs be the pack that consists of all elements of Rs except the last element. Equivalent to
Let Fs be the pack that consists of all elements of Rs except the last element. Equivalent to

[edit] Template parameters

Const	-	whether the iterator is a constant iterator

[edit] Nested types

Exposition-only types
Type	Definition
base-iter	std::variant<ranges::iterator_t<_maybe-const_ <Const, Views>>...>(exposition-only member type*)
Iterator property types
Type	Definition
iterator_concept	an iterator tag, see below
iterator_category(conditionally present)	an iterator tag, see below
value_type	concat-value-t <_maybe-const_ <Const, Views>...>
difference_type	std::common_type_t<ranges::range_difference_t<_maybe-const_ <Const, Views>>...>

[edit] Determining the iterator concept

iterator_concept is defined as follows:

If _[concat-is-random-access](iterator.html#concat-is-random-access)_ <Const, Views...> is modeled, iterator_concept denotes std::random_access_iterator_tag.
Otherwise, if _[concat-is-bidirectional](iterator.html#concat-is-bidirectional)_ <Const, Views...> is modeled, iterator_concept denotes std::bidirectional_iterator_tag.
Otherwise, if _[all-forward](../../ranges.html#all-forward "cpp/ranges")_ <Const, Views...> is modeled, iterator_concept denotes std::forward_iterator_tag.
Otherwise, iterator_concept denotes std::input_iterator_tag.

[edit] Determining the iterator category

iterator_category is defined if and only if _[all-forward](../../ranges.html#all-forward "cpp/ranges")_ <Const, Views...> is modeled. In this case, it is defined as follows:

If std::is_reference_v<_[concat-reference-t](../concat%5Fview.html#concat-reference-t "cpp/ranges/concat view")_ <_[maybe-const](../../ranges.html#maybe-const "cpp/ranges")_ <Const, Views>...>> is false, iterator_category denotes std::input_iterator_tag.
Otherwise, let Cs denote the pack of types std::iterator_traits<ranges::iterator_t<_[maybe-const](../../ranges.html#maybe-const "cpp/ranges")_ <Const, Views>>>::iterator_category...:
- If (std::derived_from<Cs, std::random_access_iterator_tag> && ...) &&
  `` _[concat-is-random-access](iterator.html#concat-is-random-access)_ <Const, Views...> is true, iterator_category denotes std::random_access_iterator_tag.
- Otherwise, if (std::derived_from<Cs, std::bidirectional_iterator_tag> && ...) &&
  `` _[concat-is-bidirectional](iterator.html#concat-is-bidirectional)_ <Const, Views...> is true, iterator_category denotes std::bidirectional_iterator_tag.
- Otherwise, if (std::derived_from<Cs, std::forward_iterator_tag> && ...) is true, iterator_category denotes std::forward_iterator_tag.
- Otherwise, iterator_category denotes std::input_iterator_tag.

[edit] Data members

Member	Definition
maybe-const <Const, ranges::concat_view>* parent_	a pointer to the parent concat_view(exposition-only member object*)
base-iter it_	an iterator into the current view(exposition-only member object*)

[edit] Member functions

(constructor)	constructs an iterator (public member function)
operator*	accesses the element (public member function)
operator[]	accesses an element by index (public member function)
operator++operator++(int)operator--operator--(int)operator+=operator-=	advances or decrements the underlying iterator (public member function) [edit]
Exposition-only function templates
_satisfy	replaces it_ with the beginning of the next view, if it_ is the end of current view(exposition-only member function*)
_prev	decrements it_ such that it points to the previous position(exposition-only member function*)
_advance-fwd	advances the current position on given offset(exposition-only member function*)
_advance-bwd	decrements the current position on given value(exposition-only member function*)

[edit] Non-member functions

[edit] Example

The preliminary version can be checked out on Compiler Explorer.

Output:

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

[edit] References

C++26 standard (ISO/IEC 14882:2026):
26.7.18.3 Class template concat_view::iterator [range.concat.iterator]