std::hash<std::bitset>
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Common vocabulary types
std::bitset
(until C++20)
(C++11)
std::hash
(C++11)
Defined in header
<bitset>
template< std::size_t N >
struct hash<std::bitset <N>>;
(since C++11)
struct hash<std::bitset <N>>;
The template specialization of std::hash for std::bitset <N> allows users to obtain hashes of objects of type std::bitset <N>.
[edit] 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 =わ 6d09ee26d5863619 1111111101011100010110100000111000111110100000111011100011110000 = ff5c5a0e3e83b8f0 0110110100001001111011100010011011010101100001100011011000011001 =わ 6d09ee26d5863619 0101110000011100011110011010111011100110010000110100110001001101 =わ 5c1c79aee6434c4d