std::bitset
<bitset>
class bitset;
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 CopyConstructible and CopyAssignable.
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.
Contents
[edit] Template parameters
[edit] Member types
[edit] Member functions
Element access
Capacity
Modifiers
Conversions
(public member function) [edit]
[edit] Non-member functions
[edit] Helper classes
[edit] 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 std::vector<bool> or boost::dynamic_bitset<> may be used instead.
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_constexpr_bitset |
202207L |
(C++23) | A more constexpr std::bitset
|
__cpp_lib_bitset |
202306L |
(C++26) | Interfacing std::bitset with std::string_view
|
[edit] Example
#include <bitset> #include <cassert> #include <cstddef> #include <iostream> int main() { typedef std::size_t length_t, position_t; // the hints // constructors: constexpr std::bitset<4> b1; constexpr std::bitset<4> b2{0xA}; // == 0B1010 std::bitset<4> b3{"0011"}; // can also be constexpr since C++23 std::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