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 )

C++