std::hash (std::string, std::wstring, std::u16string, std::u32string, std::pmr::string, std::pmr::wstring, std::pmr::u16string, std::pmr::u32string)
< cpp | string | basic string
Defined in header <string>
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template<> struct hash<std::string>; template<> struct hash<std::wstring>; |
(since C++11) | |
template<> struct hash<std::pmr::string>; template<> struct hash<std::pmr::wstring>; |
(since C++20) | |
The template specializations of std::hash for the various string classes allow users to obtain hashes of strings.
These hashes equal the hashes of corresponding std::basic_string_view classes: If S is one of these string types, SV is the corresponding string view type, and s is an object of type S, then std::hash<S>()(s) == std::hash<SV>()(SV(s)). |
(since C++17) |
Example
The following code shows one possible output of a hash function used on a string:
Run this code
#include <iostream> #include <string> #include <functional> int main() { std::string s = "Stand back! I've got jimmies!"; std::hash<std::string> hash_fn; size_t hash = hash_fn(s); std::cout << hash << '\n'; }
Output:
325378910
See also
(C++11) |
hash function object (class template) |