std::ranges...w::iterator(3)

🌸 NAME 🌸

std::ranges::elements_view::iterator — okay bestie, the original literally says the name twice, so here it is: std::ranges::elements_view::iterator. This page is from the C++ Standard Libary manual (yes, that’s the manual name, typo and all 🫶), and it’s all about the /*iterator*/ type that elements_view hands out.

✨ Synopsis ✨

template< bool Const >  (exposition only*)
class /*iterator*/;

It’s the return type of elements_view::begin, and of elements_view::end when the underlying view is a common_range.

The type /*iterator*/<true> is returned by the const-qualified overloads. The type /*iterator*/<false> is returned by the non-const-qualified overloads.

💖 Member types 💖

• Base (private) — const V if Const is true, otherwise V. (exposition-only member type*)
• iterator_concept — denotes:
  • std::random_access_iterator_tag, if Base models random_access_range. Otherwise,
  • std::bidirectional_iterator_tag, if Base models bidirectional_range. Otherwise,
  • std::forward_iterator_tag, if Base models forward_range. Otherwise,
  • std::input_iterator_tag.
• iterator_category — not defined, if Base does not model forward_range. Otherwise,
  • std::input_iterator_tag, if std::get<N>(*current_) is an rvalue. Otherwise, let C be the type std::iterator_traits<std::iterator_t<Base>>::iterator_category.
  • std::random_access_iterator_tag, if C models std::derived_from<std::random_access_iterator_tag>. Otherwise,
  • C.
• value_type — std::remove_cvref_t<std::tuple_element_t<N, ranges::range_value_t<Base>>>
• difference_type — ranges::range_difference_t<Base>

🎀 Data members 🎀

• current_ (private) — an iterator of type ranges::iterator_t<Base> to current element of underlying sequence. (exposition-only member object*)

👑 Member functions 👑

• constructor (C++20) — constructs an iterator (public member function)
• base (C++20) — returns the underlying iterator (public member function)
• operator* (C++20) — accesses the N^th tuple element (public member function)
• operator[] (C++20) — accesses an element by index (public member function)
• operator++, operator++(int), operator--, operator--(int), operator+=, operator-= (C++20) — advances or decrements the underlying iterator (public member function)

🌈 Non-member functions 🌈

• operator==, operator<, operator>, operator<=, operator>=, operator<=> (C++20) — compares the underlying iterators (function)
• operator+, operator- (C++20) — performs iterator arithmetic (function)

💀 Defect reports 💀

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

• P2259R1, applied to C++20 — behavior as published: "member iterator_category is always defined"; correct behavior: "defined only if Base models forward_range".
• LWG 3555, applied to C++20 — behavior as published: "the definition of iterator_concept ignores const"; correct behavior: "made to consider".

🦋 See also 🦋

• iterator (C++20) — the return type of ranges::transform_view::begin, and of ranges::transform_view::end when the underlying view is a common_range (private member class template).

💖 source/version/date: http://cppreference.com · 2024.06.10 · footer page tag: std::ranges...w::iterator(3) — byeee bestie, go slay some iterators 💅✨