20 General utilities library [utilities]

20.9 Bitsets [bitset]

20.9.2 Class template bitset [template.bitset] General [template.bitset.general]

namespace std { template<size_t N> class bitset { public: // bit reference class reference { friend class bitset; reference() noexcept; public: reference(const reference&) = default; ~reference(); reference& operator=(bool x) noexcept; // for b[i] = x; reference& operator=(const reference&) noexcept; // for b[i] = b[j]; bool operator~() const noexcept; // flips the bit operator bool() const noexcept; // for x = b[i]; reference& flip() noexcept; // for b[i].flip(); }; // [bitset.cons], constructors constexpr bitset() noexcept; constexpr bitset(unsigned long long val) noexcept; template<class charT, class traits, class Allocator> explicit bitset( const basic_string<charT, traits, Allocator>& str, typename basic_string<charT, traits, Allocator>::size_type pos = 0, typename basic_string<charT, traits, Allocator>::size_type n = basic_string<charT, traits, Allocator>::npos, charT zero = charT('0'), charT one = charT('1')); template<class charT> explicit bitset( const charT* str, typename basic_string<charT>::size_type n = basic_string<charT>::npos, charT zero = charT('0'), charT one = charT('1')); // [bitset.members], bitset operations bitset& operator&=(const bitset& rhs) noexcept; bitset& operator|=(const bitset& rhs) noexcept; bitset& operator^=(const bitset& rhs) noexcept; bitset& operator<<=(size_t pos) noexcept; bitset& operator>>=(size_t pos) noexcept; bitset& set() noexcept; bitset& set(size_t pos, bool val = true); bitset& reset() noexcept; bitset& reset(size_t pos); bitset operator~() const noexcept; bitset& flip() noexcept; bitset& flip(size_t pos); // element access constexpr bool operator[](size_t pos) const; // for b[i]; reference operator[](size_t pos); // for b[i]; unsigned long to_ulong() const; unsigned long long to_ullong() const; template<class charT = char, class traits = char_traits<charT>, class Allocator = allocator<charT>> basic_string<charT, traits, Allocator> to_string(charT zero = charT('0'), charT one = charT('1')) const; size_t count() const noexcept; constexpr size_t size() const noexcept; bool operator==(const bitset& rhs) const noexcept; bool test(size_t pos) const; bool all() const noexcept; bool any() const noexcept; bool none() const noexcept; bitset operator<<(size_t pos) const noexcept; bitset operator>>(size_t pos) const noexcept; }; // [bitset.hash], hash support template<class T> struct hash; template<size_t N> struct hash<bitset<N>>; }
The class template bitset<N> describes an object that can store a sequence consisting of a fixed number of bits, N.
Each bit represents either the value zero (reset) or one (set).
To toggle a bit is to change the value zero to one, or the value one to zero.
Each bit has a non-negative position pos.
When converting between an object of class bitset<N> and a value of some integral type, bit position pos corresponds to the bit value 1 << pos.
The integral value corresponding to two or more bits is the sum of their bit values.
The functions described in [template.bitset] can report three kinds of errors, each associated with a distinct exception: