C++

Reference

<bitset>

bitset

class template
<bitset>

std::bitset

template <size_t N> class bitset;
Bitset
A bitset stores bits (elements with only two possible values: 0 or 1, true or false, ...).

The class emulates an array of bool elements, but optimized for space allocation: generally, each element occupies only one bit (which, on most systems, is eight times less than the smallest elemental type: char).

Each bit position can be accessed individually: for example, for a given bitset named foo, the expression foo[3] accesses its fourth bit, just like a regular array accesses its elements. But because no elemental type is a single bit in most C++ environments, the individual elements are accessed as special references type (see bitset::reference).

Bitsets have the feature of being able to be constructed from and converted to both integer values and binary strings (see its constructor and members to_ulong and to_string). They can also be directly inserted and extracted from streams in binary format (see applicable operators).

The size of a bitset is fixed at compile-time (determined by its template parameter). For a class that also optimizes for space allocation and allows for dynamic resizing, see the bool specialization of vector (vector<bool>).

Template parameters

N
Size of the bitset, in terms of number of bits.
It is returned by member function bitset::size.
size_t is an unsigned integral type.

Member types

reference
Reference-like type (public member class)

Member functions

(constructor)
Construct bitset (public member function)
applicable operators
Bitset operators (function)

Bit access

operator[]
Access bit (public member function)
count
Count bits set (public member function)
size
Return size (public member function)
test
Return bit value (public member function)
any
Test if any bit is set (public member function)
none
Test if no bit is set (public member function)
all
Test if all bits are set (public member function)

Bit operations

set
Set bits (public member function)
reset
Reset bits (public member function)
flip
Flip bits (public member function)

Bitset operations

to_string
Convert to string (public member function)
to_ulong
Convert to unsigned long integer (public member function)
to_ullong
Convert to unsigned long long (public member function)

Non-member function overloads

applicable operators
Bitset operators (function)

Non-member class specializations

hash<bitset>
Hash for bitset (class template specialization)