Standard library header <string_view> (C++17)
From cppreference.net
此头文件是 字符串 库的组成部分。
包含文件 |
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(C++20)
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三路比较运算符 支持 | |
类 |
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(C++17)
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只读字符串视图
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| 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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字符串视图的哈希支持
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前向声明 |
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定义于头文件
<functional>
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(C++11)
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哈希函数对象
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函数 |
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(C++17)
(C++20 中移除)
(C++20 中移除)
(C++20 中移除)
(C++20 中移除)
(C++20 中移除)
(C++20)
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按字典序比较两个字符串视图
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(C++17)
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对字符串视图执行流输出
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交换两个对象的值
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范围访问 |
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(C++11)
(C++14)
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返回指向容器或数组起始的迭代器
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(C++11)
(C++14)
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返回指向容器或数组末尾的迭代器
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(C++14)
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返回指向容器或数组起始的反向迭代器
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概要
#include <compare> namespace std { // 类模板 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; // 非成员比较函数 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 /* 见描述 */ operator<=>(basic_string_view<CharT, Traits> x, basic_string_view<CharT, Traits> y) noexcept; // 充分的比较函数附加重载 // 插入器和提取器 template<class CharT, class Traits> basic_ostream<CharT, Traits>& operator<<(basic_ostream<CharT, Traits>& os, basic_string_view<CharT, Traits> str); // basic_string_view 类型别名 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>; // 哈希支持 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 { // basic_string_view 字面量后缀 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; } } }
类模板 std::basic_string_view
namespace std { template<class CharT, class Traits = char_traits<CharT>> class basic_string_view { public: // 类型定义 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 = /* 实现定义 */ 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); // 构造与赋值 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); // 迭代器支持 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; // 容量 constexpr size_type size() const noexcept; constexpr size_type length() const noexcept; constexpr size_type max_size() const noexcept; constexpr bool empty() const noexcept; // 元素访问 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; // 修改器 constexpr void remove_prefix(size_type n); constexpr void remove_suffix(size_type n); constexpr void swap(basic_string_view& s) noexcept; // 字符串操作 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<span class="sy4