标准库头文件 <string>

 

C++

语言

标准库头文件

概念

工具库

字符串库

容器库

算法库

迭代器库

数值库

输入/输出库

本地化库

正则表达式库 (C++11)

原子操作库 (C++11)

线程支持库 (C++11)

文件系统库 (C++17)

技术规范

 

标准库头文件

语言支持
<cstddef> <limits> <climits>	<cfloat> <cstdint> <new>	<typeinfo> <exception> <initializer_list>	<csignal> <csetjmp> <cstdarg>
诊断
<stdexcept>	<cassert>	<cerrno>	<system_error>
通用工具
<utility> <memory> <memory_resource> <scoped_allocator>	<tuple> <optional> <any> <variant>	<bitset> <functional> <type_traits> <ratio>	<chrono> <ctime> <typeindex> <cstdlib>
字符串
<string> <string_view>	<cctype> <cwctype>	<cwchar> <cuchar>	<cstring> <charconv>
本地化
<locale>	<codecvt>	<clocale>
容器
<array> <deque> <vector>	<forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
迭代器
<iterator>
算法
<algorithm>	<execution>
数值
<complex> <random>	<valarray> <numeric>	<cfenv> <cmath>
输入/输出
<iosfwd> <iostream> <syncstream> <ios>	<streambuf> <istream> <ostream>	<iomanip> <sstream> <fstream>	<filesystem> <cstdio> <cinttypes>
正则表达式
<regex>
线程支持
<thread> <atomic>	<mutex> <shared_mutex>	<condition_variable> <future>
C 兼容
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

 

此头文件是字符串库的一部分。

包含

<initializer_list>

(C++11 起)

类

名称	描述
std::char_traits	描述字符类型属性的类模板(类模板)
std::char_traits<char>	(类模板特化)
std::char_traits<wchar_t>	(类模板特化)
std::char_traits<char16_t> (C++11)	(类模板特化)
std::char_traits<char32_t> (C++11)	(类模板特化)
std::basic_string	表示文本字符串对象的类模板(类模板)
std::string	std::basic_string<char> (typedef)
std::wstring	std::basic_string<wchar_t> (typedef)
std::u16string (C++11)	std::basic_string<char16_t> (typedef)
std::u32string (C++11)	std::basic_string<char32_t> (typedef)
std::hash<std::string> (C++11)	(类模板特化)
std::hash<std::u16string> (C++11)	(类模板特化)
std::hash<std::u32string> (C++11)	(类模板特化)
std::hash<std::wstring> (C++11)	(类模板特化)

函数

operator+	连接两个字符串或者一个字符串和一个字符 (函数模板)
operator== operator!= operator< operator> operator<= operator>=	以字典序比较二个字符串 (函数模板)
std::swap(std::basic_string)	特化 std::swap 算法 (函数模板)
输入/输出
operator<< operator>>	进行 string 上的流输入与输出 (函数模板)
getline	从 I/O 流读取数据到字符串 (函数模板)
数值转换
stoi stol stoll (C++11) (C++11) (C++11)	转换字符串为有符号整数 (函数)
stoul stoull (C++11) (C++11)	转换字符串为无符号整数 (函数)
stof stod stold (C++11) (C++11) (C++11)	转换字符串为浮点值 (函数)
to_string (C++11)	转换整数或浮点值为 string (函数)
to_wstring (C++11)	转换整数或浮点值为 wstring (函数)

字面量

定义于内联命名空间 std::literals::string_literals
operator""s (C++14)	转换字符数组字面量为 basic_string (函数)

概要

#include <initializer_list>
 
namespace std {
 
    // 字符特性：
    template<class charT> struct char_traits;
    template <> struct char_traits<char>;
    template <> struct char_traits<char16_t>;
    template <> struct char_traits<char32_t>;
    template <> struct char_traits<wchar_t>;
 
    // basic_string:
    template<class charT, class traits = char_traits<charT>,
        class Allocator = allocator<charT> >
            class basic_string;
 
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(const basic_string<charT,traits,Allocator>& lhs,
                    const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(basic_string<charT,traits,Allocator>&& lhs,
                    const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(const basic_string<charT,traits,Allocator>& lhs,
                    basic_string<charT,traits,Allocator>&& rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(basic_string<charT,traits,Allocator>&& lhs,
                    basic_string<charT,traits,Allocator>&& rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(const charT* lhs,
                    const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(const charT* lhs,
                    basic_string<charT,traits,Allocator>&& rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(charT lhs, const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(charT lhs, basic_string<charT,traits,Allocator>&& rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(const basic_string<charT,traits,Allocator>& lhs,
                    const charT* rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(basic_string<charT,traits,Allocator>&& lhs,
                    const charT* rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(const basic_string<charT,traits,Allocator>& lhs, charT rhs);
    template<class charT, class traits, class Allocator>
        basic_string<charT,traits,Allocator>
            operator+(basic_string<charT,traits,Allocator>&& lhs, charT rhs);
 
    template<class charT, class traits, class Allocator>
        bool operator==(const basic_string<charT,traits,Allocator>& lhs,
            const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        bool operator==(const charT* lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        bool operator==(const basic_string<charT,traits,Allocator>& lhs
                        const charT* rhs);
    template<class charT, class traits, class Allocator>
        bool operator!=(const basic_string<charT,traits,Allocator>& lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        bool operator!=(const charT* lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        bool operator!=(const basic_string<charT,traits,Allocator>& lhs,
                        const charT* rhs);
 
    template<class charT, class traits, class Allocator>
        bool operator< (const basic_string<charT,traits,Allocator>& lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        bool operator< (const basic_string<charT,traits,Allocator>& lhs,
                        const charT* rhs);
    template<class charT, class traits, class Allocator>
        bool operator< (const charT* lhs,
            const basic_string<charT,traits,Allocator>& rhs);
 
    template<class charT, class traits, class Allocator>
        bool operator> (const basic_string<charT,traits,Allocator>& lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        bool operator> (const basic_string<charT,traits,Allocator>& lhs,
                        const charT* rhs);
    template<class charT, class traits, class Allocator>
        bool operator> (const charT* lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
 
    template<class charT, class traits, class Allocator>
        bool operator<=(const basic_string<charT,traits,Allocator>& lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        bool operator<=(const basic_string<charT,traits,Allocator>& lhs,
                        const charT* rhs);
    template<class charT, class traits, class Allocator>
        bool operator<=(const charT* lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        bool operator>=(const basic_string<charT,traits,Allocator>& lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
    template<class charT, class traits, class Allocator>
        bool operator>=(const basic_string<charT,traits,Allocator>& lhs,
                        const charT* rhs);
    template<class charT, class traits, class Allocator>
        bool operator>=(const charT* lhs,
                        const basic_string<charT,traits,Allocator>& rhs);
 
    // 交换：
    template<class charT, class traits, class Allocator>
        void swap(basic_string<charT,traits,Allocator>& lhs,
                basic_string<charT,traits,Allocator>& rhs);
 
    // 插入器与释出器：
    template<class charT, class traits, class Allocator>
        basic_istream<charT,traits>&
            operator>>(basic_istream<charT,traits>&& is,
                    basic_string<charT,traits,Allocator>& str);
    template<class charT, class traits, class Allocator>
        basic_ostream<charT, traits>&
            operator<<(basic_ostream<charT, traits>&& os,
                    const basic_string<charT,traits,Allocator>& str);
    template<class charT, class traits, class Allocator>
        basic_istream<charT,traits>&
            getline(basic_istream<charT,traits>& is,
                    basic_string<charT,traits,Allocator>& str,
                    charT delim);
    template<class charT, class traits, class Allocator>
        basic_istream<charT,traits>&
            getline(basic_istream<charT,traits>&& is,
                    basic_string<charT,traits,Allocator>& str,
                    charT delim);
    template<class charT, class traits, class Allocator>
        basic_istream<charT,traits>&
            getline(basic_istream<charT,traits>& is,
                    basic_string<charT,traits,Allocator>& str);
    template<class charT, class traits, class Allocator>
        basic_istream<charT,traits>&
            getline(basic_istream<charT,traits>&& is,
                    basic_string<charT,traits,Allocator>& str);
 
    // basic_string typedef名
    typedef basic_string<char> string;
    typedef basic_string<char16_t> u16string;
    typedef basic_string<char32_t> u32string;
    typedef basic_string<wchar_t> wstring;
 
    // 数值转换：
    int stoi(const string& str, size_t *idx = 0, int base = 10);
    long stol(const string& str, size_t *idx = 0, int base = 10);
    unsigned long stoul(const string& str, size_t *idx = 0, int base = 10);
    long long stoll(const string& str, size_t *idx = 0, int base = 10);
    unsigned long long stoull(const string& str, size_t *idx = 0, int base = 10);
    float stof(const string& str, size_t *idx = 0);
    double stod(const string& str, size_t *idx = 0);
    long double stold(const string& str, size_t *idx = 0);
    string to_string(int val);
    string to_string(unsigned val);
    string to_string(long val);
    string to_string(unsigned long val);
    string to_string(long long val);
    string to_string(unsigned long long val);
    string to_string(float val);
    string to_string(double val);
    string to_string(long double val);
 
    int stoi(const wstring& str, size_t *idx = 0, int base = 10);
    long stol(const wstring& str, size_t *idx = 0, int base = 10);
    unsigned long stoul(const wstring& str, size_t *idx = 0, int base = 10);
    long long stoll(const wstring& str, size_t *idx = 0, int base = 10);
    unsigned long long stoull(const wstring& str, size_t *idx = 0, int base = 10);
    float stof(const wstring& str, size_t *idx = 0);
    double stod(const wstring& str, size_t *idx = 0);
    long double stold(const wstring& str, size_t *idx = 0);
    wstring to_wstring(int val);
    wstring to_wstring(unsigned val);
    wstring to_wstring(long val);
    wstring to_wstring(unsigned long val);
    wstring to_wstring(long long val);
    wstring to_wstring(unsigned long long val);
    wstring to_wstring(float val);
    wstring to_wstring(double val);
    wstring to_wstring(long double val);
 
    // 哈希支持：
    template <class T> struct hash;
    template <> struct hash<string>;
    template <> struct hash<u16string>;
    template <> struct hash<u32string>;
    template <> struct hash<wstring>;
 
    inline namespace literals {
    inline namespace string_literals {
 
    string operator "" s(const char* str, size_t len);
    u16string operator "" s(const char16_t* str, size_t len);
    u32string operator "" s(const char32_t* str, size_t len);
    wstring operator "" s(const wchar_t* str, size_t len);
 
   } // inline namespace string_literals
   } // inline namespace literals
} // namespace std