std::hash (std::string, std::wstring, std::u16string, std::u32string)

 

C++

Language

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

char_traits

 

std::basic_string

Member functions

basic_string::basic_string

basic_string::operator=

basic_string::assign

basic_string::get_allocator

Element access

basic_string::at

basic_string::operator[]

basic_string::front (C++11)

basic_string::back (C++11)

basic_string::data

basic_string::c_str

Iterators

basic_string::begin basic_string::cbegin (C++11)

basic_string::end basic_string::cend (C++11)

basic_string::rbegin basic_string::crbegin (C++11)

basic_string::rend basic_string::crend (C++11)

Capacity

basic_string::empty

basic_string::size

basic_string::length

basic_string::max_size

basic_string::reserve

basic_string::capacity

basic_string::shrink_to_fit (C++11)

Operations

basic_string::clear

basic_string::insert

basic_string::erase

basic_string::push_back

basic_string::pop_back (C++11)

basic_string::append

basic_string::operator+=

basic_string::compare

basic_string::replace

basic_string::substr

basic_string::copy

basic_string::resize

basic_string::swap

Search

basic_string::find

basic_string::rfind

basic_string::find_first_of

basic_string::find_first_not_of

basic_string::find_last_of

basic_string::find_last_not_of

Constants

basic_string::npos

Non-member functions

operator+

operator== operator!= operator< operator> operator<= operator>=

swap(std::basic_string)

operator<< operator>>

getline

stoi stol stoll (C++11) (C++11) (C++11)

stoul stoull (C++11) (C++11)

stof stod stold (C++11) (C++11) (C++11)

to_string (C++11)

to_wstring (C++11)

Helper classes

hash<std::string> hash<std::wstring> hash<std::u32string> hash<std::u16string> (C++11)

 

Defined in header <string>
template<> struct hash<std::string>; template<> struct hash<std::wstring>; template<> struct hash<std::u16string>; template<> struct hash<std::u32string>;		(since C++11)

The template specializations of std::hash for the various string classes allow users to obtain hashes of strings.

Example

The following code shows one possible output of a hash function used on a string:

#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

hash (C++11)	hash function object (class template)