std::hash(std::basic_string)

`<string>`
`template< class A > struct hash<std::basic_string<char, std::char_traits<char>, A>>;`	(1)	( C++11)
`template< class A > struct hash<std::basic_string<char16_t, std::char_traits<char16_t>, A>>;`	(2)	( C++11)
`template< class A > struct hash<std::basic_string<char32_t, std::char_traits<char32_t>, A>>;`	(3)	( C++11)
`template< class A > struct hash<std::basic_string<wchar_t, std::char_traits<wchar_t>, A>>;`	(4)	( C++11)
`template< class A > struct hash<std::basic_string<char8_t, std::char_traits<char8_t>, A>>;`	(5)	( C++20)

std::hash .

std::basic_string_view: S , SV , s S, std::hash<S>()(s) == std::hash<SV>()(SV(s)).

( C++17)

-, :

#include <iostream>
#include <string>
#include <string_view>
#include <functional>
#include <memory_resource>
using namespace std::literals;
 
int main()
{
    auto sv = "!    !"sv;
    std::string s(sv);
    std::pmr::string pmrs(sv); //    
 
    std::cout << std::hash<std::string_view>{}(sv) << '\n';
    std::cout << std::hash<std::string>{}(s) << '\n';
    std::cout << std::hash<std::pmr::string>{}(pmrs) << '\n';
}

:

11158872145337085299
11158872145337085299
11158872145337085299

C++:


LWG 3705	C++11	std::basic_string

hash (C++11)	- ( ) []
std::hash<std::string_view>std::hash<std::wstring_view>std::hash<std::u8string_view>std::hash<std::u16string_view>std::hash<std::u32string_view> (C++17)(C++17)(C++20)(C++17)(C++17)	( ) []







(C++20)

(C++20)
(C++11)





(C++20)


/

(C++11)
(C++11)
(C++11)
(C++17)

cppreference.com

std::hash(std::basic_string)