[string.view.iterators]

# 27 Strings library [[strings]](./#strings)

## 27.3 String view classes [[string.view]](string.view#iterators)

### 27.3.3 Class template basic_string_view [[string.view.template]](string.view.template#string.view.iterators)

#### 27.3.3.4 Iterator support [string.view.iterators]

[ð](#lib:const_iterator,basic_string_view)

`using const_iterator = implementation-defined;
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L928)

A type that meets the requirements
of a constant[*Cpp17RandomAccessIterator*](random.access.iterators#:Cpp17RandomAccessIterator "24.3.5.7 Random access iterators [random.access.iterators]") ([[random.access.iterators]](random.access.iterators "24.3.5.7 Random access iterators")),
models [contiguous_iterator](iterator.concept.contiguous#concept:contiguous_iterator "24.3.4.14 Concept contiguous_­iterator [iterator.concept.contiguous]") ([[iterator.concept.contiguous]](iterator.concept.contiguous "24.3.4.14 Concept contiguous_­iterator")), and
meets the constexpr iterator requirements ([[iterator.requirements.general]](iterator.requirements.general "24.3.1 General")),
whose value_type is the template parameter charT[.](#1.sentence-1)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L936)

All requirements on container iterators ([[container.requirements]](container.requirements "23.2 Requirements")) apply to basic_string_view​::​const_iterator as well[.](#2.sentence-1)

[ð](#lib:begin,basic_string_view)

`constexpr const_iterator begin() const noexcept;
constexpr const_iterator cbegin() const noexcept;
`

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L948)

*Returns*: An iterator such that

- [(3.1)](#3.1)

if !empty(), addressof(*begin()) == *data_*,

- [(3.2)](#3.2)

otherwise, an unspecified value such that [begin(), end()) is a valid range[.](#3.sentence-1)

[ð](#lib:end,basic_string_view)

`constexpr const_iterator end() const noexcept;
constexpr const_iterator cend() const noexcept;
`

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L965)

*Returns*: begin() + size()[.](#4.sentence-1)

[ð](#lib:rbegin,basic_string_view)

`constexpr const_reverse_iterator rbegin() const noexcept;
constexpr const_reverse_iterator crbegin() const noexcept;
`

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L978)

*Returns*: const_reverse_iterator(end())[.](#5.sentence-1)

[ð](#lib:rend,basic_string_view)

`constexpr const_reverse_iterator rend() const noexcept;
constexpr const_reverse_iterator crend() const noexcept;
`

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/strings.tex#L991)

*Returns*: const_reverse_iterator(begin())[.](#6.sentence-1)
