std::hash (std::bitset)

 

C++

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Technical Specifications

 

Utilities library

Language support Type support (basic types, RTTI, type traits) Library feature-test macros (C++20) Dynamic memory management Program utilities Error handling Coroutine support (C++20) Variadic functions launder (C++17) initializer_list (C++11) source_location (C++20) Three-way comparison (C++20) three_way_comparablethree_way_comparable_with (C++20)(C++20) strong_ordering (C++20) weak_ordering (C++20) partial_ordering (C++20) common_comparison_category (C++20) compare_three_way_result (C++20) compare_three_way (C++20) strong_order (C++20) weak_order (C++20) partial_order (C++20) compare_strong_order_fallback (C++20) compare_weak_order_fallback (C++20) compare_partial_order_fallback (C++20) is_eqis_neqis_ltis_lteqis_gtis_gteq (C++20)(C++20)(C++20)(C++20)(C++20)(C++20)

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std::bitset

Member types

bitset::reference

Member functions

bitset::bitset

bitset::operator==bitset::operator!= (until C++20)

Element access

bitset::operator[]

bitset::test

bitset::allbitset::anybitset::none (C++11)

bitset::count

Capacity

bitset::size

Modifiers

bitset::operator&=bitset::operator|=bitset::operator^=bitset::operator~

bitset::operator<<=bitset::operator>>=bitset::operator<<bitset::operator>>

bitset::set

bitset::reset

bitset::flip

Conversions

bitset::to_string

bitset::to_ulong

bitset::to_ullong (C++11)

Non-member functions

operator&operator|operator^

operator<<operator>>

Helper classes

std::hash (C++11)

 

template<size_t N> struct hash<bitset<N>>;		(since C++11)

The template specialization of std::hash for std::bitset<N> allows users to obtain hashes of objects of type std::bitset<N>.

Example

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

Run this code

#include <iostream>
#include <bitset>
#include <functional>
 
int main()
{
    std::bitset<4> b1(1);
    std::bitset<4> b2(2);
    std::bitset<4> b3(b2);
 
    std::hash<std::bitset<4>> hash_fn;
 
    size_t h1 = hash_fn(b1);
    size_t h2 = hash_fn(b2);
    size_t h3 = hash_fn(b3);
 
    std::cout << h1 << '\n';
    std::cout << h2 << '\n';
    std::cout << h3 << '\n';
}

Possible output:

67918732
118251589
118251589

See also

hash (C++11)

hash function object (class template)