Standard library header <string_view> (C++17)
From cppreference.com
This header is part of the strings library.
Includes |
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(C++20)
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Three-way comparison operator support |
Classes |
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(C++17)
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read-only string view
(class template) |
| std::string_view (C++17) | std:: basic_string_view < char > |
| std::u8string_view (C++20) | std:: basic_string_view < char8_t > |
| std::u16string_view (C++17) | std:: basic_string_view < char16_t > |
| std::u32string_view (C++17) | std:: basic_string_view < char32_t > |
| std::wstring_view (C++17) | std:: basic_string_view < wchar_t > |
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(C++17)
(C++17)
(C++20)
(C++17)
(C++17)
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hash support for string views
(class template specialization) |
Forward declarations |
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Defined in header
<functional>
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(C++11)
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hash function object
(class template) |
Functions |
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(C++17)
(removed in C++20)
(removed in C++20)
(removed in C++20)
(removed in C++20)
(removed in C++20)
(C++20)
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lexicographically compares two string views
(function template) |
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(C++17)
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performs stream output on string views
(function template) |
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swaps the values of two objects
(function template) |
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Range access |
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(C++11)
(C++14)
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returns an iterator to the beginning of a container or array
(function template) |
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(C++11)
(C++14)
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returns an iterator to the end of a container or array
(function template) |
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(C++14)
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returns a reverse iterator to the beginning of a container or array
(function template) |
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(C++14)
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returns a reverse end iterator for a container or array
(function template) |
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(C++17)
(C++20)
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returns the size of a container or array
(function template) |
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(C++17)
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checks whether the container is empty
(function template) |
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(C++17)
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obtains the pointer to the underlying array
(function template) |
Literals |
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Defined in inline namespace
std::literals::string_view_literals
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(C++17)
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creates a string view of a character array literal
(function) |
Synopsis
#include <compare> namespace std { // class template basic_string_view template<class CharT, class Traits = char_traits<CharT>> class basic_string_view; template<class CharT, class Traits> inline constexpr bool ranges::enable_view<basic_string_view<CharT, Traits>> = true; template<class CharT, class Traits> inline constexpr bool ranges::enable_borrowed_range<basic_string_view<CharT, Traits>> = true; // non-member comparison functions template<class CharT, class Traits> constexpr bool operator==(basic_string_view<CharT, Traits> x, basic_string_view<CharT, Traits> y) noexcept; template<class CharT, class Traits> constexpr /* see description */ operator<=>(basic_string_view<CharT, Traits> x, basic_string_view<CharT, Traits> y) noexcept; // sufficient additional overloads of comparison functions // inserters and extractors template<class CharT, class Traits> basic_ostream<CharT, Traits>& operator<<(basic_ostream<CharT, Traits>& os, basic_string_view<CharT, Traits> str); // basic_string_view typedef names using string_view = basic_string_view<char>; using u8string_view = basic_string_view<char8_t>; using u16string_view = basic_string_view<char16_t>; using u32string_view = basic_string_view<char32_t>; using wstring_view = basic_string_view<wchar_t>; // hash support template<class T> struct hash; template<> struct hash<string_view>; template<> struct hash<u8string_view>; template<> struct hash<u16string_view>; template<> struct hash<u32string_view>; template<> struct hash<wstring_view>; inline namespace literals { inline namespace string_view_literals { // suffix for basic_string_view literals constexpr string_view operator""sv(const char* str, size_t len) noexcept; constexpr u8string_view operator""sv(const char8_t* str, size_t len) noexcept; constexpr u16string_view operator""sv(const char16_t* str, size_t len) noexcept; constexpr u32string_view operator""sv(const char32_t* str, size_t len) noexcept; constexpr wstring_view operator""sv(const wchar_t* str, size_t len) noexcept; } } }
Class template std::basic_string_view
namespace std { template<class CharT, class Traits = char_traits<CharT>> class basic_string_view { public: // types using Traits_type = Traits; using value_type = CharT; using pointer = value_type*; using const_pointer = const value_type*; using reference = value_type&; using const_reference = const value_type&; using const_iterator = /* implementation-defined */ using iterator = const_iterator; using const_reverse_iterator = reverse_iterator<const_iterator>; using reverse_iterator = const_reverse_iterator; using size_type = size_t; using difference_type = ptrdiff_t; static constexpr size_type npos = size_type(-1); // construction and assignment constexpr basic_string_view() noexcept; constexpr basic_string_view(const basic_string_view&) noexcept = default; constexpr basic_string_view& operator=(const basic_string_view&) noexcept = default; constexpr basic_string_view(const CharT* str); constexpr basic_string_view(nullptr_t) = delete; constexpr basic_string_view(const CharT* str, size_type len); template<class It, class End> constexpr basic_string_view(It begin, End end); template<class R> constexpr explicit basic_string_view(R&& r); // iterator support constexpr const_iterator begin() const noexcept; constexpr const_iterator end() const noexcept; constexpr const_iterator cbegin() const noexcept; constexpr const_iterator cend() const noexcept; constexpr const_reverse_iterator rbegin() const noexcept; constexpr const_reverse_iterator rend() const noexcept; constexpr const_reverse_iterator crbegin() const noexcept; constexpr const_reverse_iterator crend() const noexcept; // capacity constexpr size_type size() const noexcept; constexpr size_type length() const noexcept; constexpr size_type max_size() const noexcept; constexpr bool empty() const noexcept; // element access constexpr const_reference operator[](size_type pos) const; constexpr const_reference at(size_type pos) const; constexpr const_reference front() const; constexpr const_reference back() const; constexpr const_pointer data() const noexcept; // modifiers constexpr void remove_prefix(size_type n); constexpr void remove_suffix(size_type n); constexpr void swap(basic_string_view& s) noexcept; // string operations constexpr size_type copy(CharT* s, size_type n, size_type pos = 0) const; constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const; constexpr int compare(basic_string_view s) const noexcept; constexpr int compare(size_type pos1, size_type n1, basic_string_view s) const; constexpr int compare(size_type pos1, size_type n1, basic_string_view s, size_type pos2, size_type n2) const; constexpr int compare(const CharT* s) const; constexpr int compare(size_type pos1, size_type n1, const CharT* s) const; constexpr int compare(size_type pos1, size_type n1, const CharT* s, size_type n2) const; constexpr bool starts_with(basic_string_view x) const noexcept; constexpr bool starts_with(CharT x) const noexcept; constexpr bool starts_with(const CharT* x) const; constexpr bool ends_with(basic_string_view x) const noexcept; constexpr bool ends_with(CharT x) const noexcept; constexpr bool ends_with(const CharT* x) const; constexpr bool contains(basic_string_view x) const noexcept; constexpr bool contains(CharT x) const noexcept; constexpr bool contains(const CharT* x) const; // searching constexpr size_type find(basic_string_view s, size_type pos = 0) const noexcept; constexpr size_type find(CharT c, size_type pos = 0) const noexcept; constexpr size_type find(const CharT* s, size_type pos, size_type n) const; constexpr size_type find(const CharT* s, size_type pos = 0) const; constexpr size_type rfind(basic_string_view s, size_type pos = npos) const noexcept; constexpr size_type rfind(CharT c, size_type pos = npos) const noexcept; constexpr size_type rfind(const CharT* s, size_type pos, size_type n) const; constexpr size_type rfind(const CharT* s, size_type pos = npos) const; constexpr size_type find_first_of(basic_string_view s, size_type pos = 0) const noexcept; constexpr size_type find_first_of(CharT c, size_type pos = 0) const noexcept; constexpr size_type find_first_of(const CharT* s, size_type pos, size_type n) const; constexpr size_type find_first_of(const CharT* s, size_type pos = 0) const; constexpr size_type find_last_of(basic_string_view s, size_type pos = npos) const noexcept; constexpr size_type find_last_of(CharT c, size_type pos = npos) const noexcept; constexpr size_type find_last_of(const CharT* s, size_type pos, size_type n) const; constexpr size_type find_last_of(const CharT* s, size_type pos = npos) const; constexpr size_type find_first_not_of(basic_string_view s, size_type pos = 0) const noexcept; constexpr size_type find_first_not_of(CharT c, size_type pos = 0) const noexcept; constexpr size_type find_first_not_of(const CharT* s, size_type pos, size_type n) const; constexpr size_type find_first_not_of(const CharT* s, size_type pos = 0) const; constexpr size_type find_last_not_of(basic_string_view s, size_type pos = npos) const noexcept; constexpr size_type find_last_not_of(CharT c, size_type pos = npos) const noexcept; constexpr size_type find_last_not_of(const CharT* s, size_type pos, size_type n) const; constexpr size_type find_last_not_of(const CharT* s, size_type pos = npos) const; private: const_pointer data_; // exposition only size_type size_; // exposition only }; // deduction guides template<class It, class End> basic_string_view(It, End) -> basic_string_view<iter_value_t<It>>; template<class R> basic_string_view(R&&) -> basic_string_view<ranges::range_value_t<R>>; }