std::ranges::concat_view<Views...>::iterator
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std::ranges::concat_view
Iterator
template< bool Const >
class /*iterator*/
(1)
(exposition only*)
class /*iterator*/
Helper concepts
template< bool Const, class... Rs >
concept /*concat-is-random-access*/ = /* see description */;
(2)
(exposition only*)
concept /*concat-is-random-access*/ = /* see description */;
template< bool Const, class... Rs >
concept /*concat-is-bidirectional*/ = /* see description */;
(3)
(exposition only*)
concept /*concat-is-bidirectional*/ = /* see description */;
1) ranges::concat_view <Views...>::
iterator is the type of the iterators returned by begin() and end() of ranges::concat_view <Views...>.2) Let
Fs be the pack that consists of all elements of Rs except the last element. Equivalent totemplate<bool Const, class... Rs>
concept concat-is-random-access = // exposition only
all-random-access <Const, Rs...> &&
(ranges::common_range <maybe-const <Const, Fs>> && ...);
3) Let
Fs be the pack that consists of all elements of Rs except the last element. Equivalent totemplate<bool Const, class... Rs>
concept concat-is-bidirectional = // exposition only
all-bidirectional <Const, Rs...> &&
(ranges::common_range <maybe-const <Const, Fs>> && ...);
Contents
[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
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<Const, Views...> is modeled,iterator_conceptdenotes std::random_access_iterator_tag . - Otherwise, if
concat-is-bidirectional<Const, Views...> is modeled,iterator_conceptdenotes std::bidirectional_iterator_tag . - Otherwise, if
all-forward<Const, Views...> is modeled,iterator_conceptdenotes std::forward_iterator_tag . - Otherwise,
iterator_conceptdenotes std::input_iterator_tag .
[edit] Determining the iterator category
iterator_category is defined if and only if all-forward <Const, Views...> is modeled. In this case, it is defined as follows:
- If std::is_reference_v <
concat-reference-t<maybe-const<Const, Views>...>> is false,iterator_categorydenotes std::input_iterator_tag . - Otherwise, let
Csdenote the pack of types std::iterator_traits <ranges::iterator_t <maybe-const<Const, Views>>>::iterator_category...:- If (std::derived_from <Cs, std::random_access_iterator_tag > && ...) &&
concat-is-random-access<Const, Views...> is true,iterator_categorydenotes std::random_access_iterator_tag . - Otherwise, if (std::derived_from <Cs, std::bidirectional_iterator_tag > && ...) &&
concat-is-bidirectional<Const, Views...> is true,iterator_categorydenotes std::bidirectional_iterator_tag . - Otherwise, if (std::derived_from <Cs, std::forward_iterator_tag > && ...) is true,
iterator_categorydenotes std::forward_iterator_tag . - Otherwise,
iterator_categorydenotes std::input_iterator_tag .
- If (std::derived_from <Cs, std::random_access_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
Exposition-only function templates
replaces
(exposition-only member function*)
it_ with the beginning of the next view, if it_ is the end of current view(exposition-only member function*)
[edit] Non-member functions
compares the underlying iterators
(function)
(function)
(C++26)
(function)
[edit] Example
The preliminary version can be checked out on Compiler Explorer.
Run this code
#include <iostream> #include <iterator> #include <ranges> int main() { namespace views = std::views; static constexpr int p[]{1, 2, 3}; static constexpr auto e = {4, 5}; auto t = views::iota (6, 9); auto cat = views::concat (p, e, t); auto dog = views::concat (cat, cat); for (auto i{dog.begin()}; i != std::default_sentinel ; ++i) std::cout << *i << ' '; std::cout << '\n'; }
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]
- 26.7.18.3 Class template