std::hash(std::bitset)

 

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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

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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)

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operator&operator|operator^

operator<<operator>>

Helper classes

std::hash (C++11)

 

Defined in header <bitset>
template< std::size_t N > struct hash<std::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 <bitset>
#include <functional>
#include <iostream>
 
int main()
{
    std::bitset<4> b1{0}, b2{42};
    std::bitset<8> b3{0}, b4{42};
 
    std::hash<std::bitset<4>> hash_fn4;
    std::hash<std::bitset<8>> hash_fn8;
    using bin64 = std::bitset<64>;
 
    std::cout
        << std::hex
        << bin64{hash_fn4(b1)} << " = " << hash_fn4(b1) << '\n'
        << bin64{hash_fn4(b2)} << " = " << hash_fn4(b2) << '\n'
        << bin64{hash_fn8(b3)} << " = " << hash_fn8(b3) << '\n'
        << bin64{hash_fn8(b4)} << " = " << hash_fn8(b4) << '\n';
}

Possible output:

0110110100001001111011100010011011010101100001100011011000011001 = 6d09ee26d5863619
1111111101011100010110100000111000111110100000111011100011110000 = ff5c5a0e3e83b8f0
0110110100001001111011100010011011010101100001100011011000011001 = 6d09ee26d5863619
0101110000011100011110011010111011100110010000110100110001001101 = 5c1c79aee6434c4d

See also

hash (C++11)

hash function object (class template)