From cppreference.com
template<std::size_tN>classbitset;The class template bitset represents a fixed-size sequence of N bits. Bitsets can be manipulated by standard logic operators and converted to and from strings and integers. For the purpose of the string representation and of naming directions for shift operations, the sequence is thought of as having its lowest indexed elements at the right, as in the binary representation of integers.
bitset meets the requirements of
and
.
All member functions of std::bitset are constexpr: it is possible to create and use std::bitset objects in the evaluation of a constant expression.
(since C++23)Template parameters
N - the number of bits to allocate storage for Member types
proxy class representing a reference to a bit
(class)Member functions
constructs the bitset
(public member function)
(removed in C++20)
compares the contents
(public member function)
Element access
accesses specific bit
(public member function)
accesses specific bit
(public member function)
checks if all, any or none of the bits are set to true
(public member function)
returns the number of bits set to true
(public member function)
Capacity
returns the number of bits that the bitset holds
(public member function)
Modifiers
operator&=operator|=operator^=operator~
performs binary AND, OR, XOR and NOT
(public member function)
operator<<=operator>>=operator<<operator>>
performs binary shift left and shift right
(public member function)
sets bits to true or given value
(public member function)
sets bits to false
(public member function)
toggles the values of bits
(public member function)
Conversions
returns a string representation of the data
(public member function)
returns an unsignedlong integer representation of the data
(public member function)
(C++11)
returns an unsignedlonglong integer representation of the data
(public member function)
Non-member functions
Helper classes
Notes
If the size of a bit-set is not known at compile time, or it is necessary to change its size at run-time, the dynamic types such as
or
may be used instead.
macro ValueStdFeature
(C++23)A more constexpr std::bitset
(C++26)Interfacing std::bitset with
Example
Run this code
#include<bitset>#include<cassert>#include<cstddef>#include<iostream>intmain(){typedefstd::size_tlength_t,position_t;// the hints// constructors:constexprstd::bitset<4>b1;constexprstd::bitset<4>b2{0xA};// == 0B1010std::bitset<4>b3{"0011"};// can also be constexpr since C++23std::bitset<8>b4{"ABBA",length_t(4),/*0:*/'A',/*1:*/'B'};// == 0B0000'0110// bitsets can be printed out to a stream:std::cout<<"b1:"<<b1<<"; b2:"<<b2<<"; b3:"<<b3<<"; b4:"<<b4<<'\n';// bitset supports bitwise operations:b3|=0b0100;assert(b3==0b0111);b3&=0b0011;assert(b3==0b0011);b3^=std::bitset<4>{0b1100};assert(b3==0b1111);// operations on the whole set:b3.reset();assert(b3==0);b3.set();assert(b3==0b1111);assert(b3.all()&&b3.any()&&!b3.none());b3.flip();assert(b3==0);// operations on individual bits:b3.set(position_t(1),true);assert(b3==0b0010);b3.set(position_t(1),false);assert(b3==0);b3.flip(position_t(2));assert(b3==0b0100);b3.reset(position_t(2));assert(b3==0);// subscript operator[] is supported:b3[2]=true;assert(true==b3[2]);// other operations:assert(b3.count()==1);assert(b3.size()==4);assert(b3.to_ullong()==0b0100ULL);assert(b3.to_string()=="0100");}Output:
b1:0000; b2:1010; b3:0011; b4:00000110 See also
space-efficient dynamic bitset
(class template specialization)
(C++20)utilities to access, manipulate, and process individual bits and bit sequences