std::bitset< _Nb >(3) Library Functions Manual std::bitset< _Nb >(3) NAME std::bitset< _Nb > - The bitset class represents a fixed-size sequence of bits. SYNOPSIS #include Inherits std::_Base_bitset<((_Nb)/(__CHAR_BIT__ *__SIZEOF_LONG__)+((_Nb) %(__CHAR_BIT__ *__SIZEOF_LONG__)==0 ? 0 :1))>. Classes class reference Public Member Functions constexpr bitset () noexcept All bits set to zero. template constexpr bitset (const _CharT *__str, typename __bitset::__string< _CharT >::size_type __n=__bitset::__string< _CharT >::npos, _CharT __zero=_CharT('0'), _CharT __one=_CharT('1')) template constexpr bitset (const std::basic_string< _CharT, _Traits, _Alloc > &__s, size_t __position, size_t __n) template constexpr bitset (const std::basic_string< _CharT, _Traits, _Alloc > &__s, size_t __position, size_t __n, _CharT __zero, _CharT __one=_CharT('1')) template constexpr bitset (const std::basic_string< _CharT, _Traits, _Alloc > &__s, size_t __position=0) constexpr bitset (unsigned long long __val) noexcept Initial bits bitwise-copied from a single word (others set to zero). constexpr size_t _Find_first () const noexcept Finds the index of the first 'on' bit. constexpr size_t _Find_next (size_t __prev) const noexcept Finds the index of the next 'on' bit after prev. constexpr bool all () const noexcept Tests whether all the bits are on. constexpr bool any () const noexcept Tests whether any of the bits are on. constexpr size_t count () const noexcept Returns the number of bits which are set. constexpr bitset< _Nb > & flip () noexcept Toggles every bit to its opposite value. constexpr bitset< _Nb > & flip (size_t __position) Toggles a given bit to its opposite value. constexpr bool none () const noexcept Tests whether any of the bits are on. constexpr bitset< _Nb > operator~ () const noexcept See the no-argument flip(). constexpr bitset< _Nb > & reset () noexcept Sets every bit to false. constexpr bitset< _Nb > & reset (size_t __position) Sets a given bit to false. constexpr bitset< _Nb > & set () noexcept Sets every bit to true. constexpr bitset< _Nb > & set (size_t __position, bool __val=true) Sets a given bit to a particular value. constexpr size_t size () const noexcept Returns the total number of bits. constexpr bool test (size_t __position) const Tests the value of a bit. template constexpr std::basic_string< _CharT, _Traits, _Alloc > to_string () const Returns a character interpretation of the bitset. template constexpr std::basic_string< _CharT, _Traits, std::allocator< _CharT > > to_string () const template constexpr std::basic_string< _CharT, std::char_traits< _CharT >, std::allocator< _CharT > > to_string () const constexpr std::basic_string< char, std::char_traits< char >, std::allocator< char > > to_string () const template constexpr std::basic_string< _CharT, _Traits, _Alloc > to_string (_CharT __zero, _CharT __one=_CharT('1')) const template constexpr std::basic_string< _CharT, _Traits, std::allocator< _CharT > > to_string (_CharT __zero, _CharT __one=_CharT('1')) const template constexpr std::basic_string< _CharT, std::char_traits< _CharT >, std::allocator< _CharT > > to_string (_CharT __zero, _CharT __one=_CharT('1')) const constexpr std::basic_string< char, std::char_traits< char >, std::allocator< char > > to_string (char __zero, char __one='1') const constexpr unsigned long long to_ullong () const constexpr unsigned long to_ulong () const Returns a numerical interpretation of the bitset. constexpr bitset< _Nb > & operator&= (const bitset< _Nb > &__rhs) noexcept constexpr bitset< _Nb > & operator|= (const bitset< _Nb > &__rhs) noexcept constexpr bitset< _Nb > & operator^= (const bitset< _Nb > &__rhs) noexcept constexpr bitset< _Nb > & operator<<= (size_t __position) noexcept constexpr bitset< _Nb > & operator>>= (size_t __position) noexcept constexpr bitset< _Nb > & _Unchecked_set (size_t __pos) noexcept constexpr bitset< _Nb > & _Unchecked_set (size_t __pos, int __val) noexcept constexpr bitset< _Nb > & _Unchecked_reset (size_t __pos) noexcept constexpr bitset< _Nb > & _Unchecked_flip (size_t __pos) noexcept constexpr bool _Unchecked_test (size_t __pos) const noexcept constexpr reference operator[] (size_t __position) Array-indexing support. constexpr bool operator[] (size_t __position) const Array-indexing support. constexpr bool operator== (const bitset< _Nb > &__rhs) const noexcept These comparisons for equality/inequality are, well, bitwise. constexpr bitset< _Nb > operator<< (size_t __position) const noexcept Self-explanatory. constexpr bitset< _Nb > operator>> (size_t __position) const noexcept Self-explanatory. Friends template std::basic_ostream< _CharT, _Traits > & operator<< (std::basic_ostream< _CharT, _Traits > &, const bitset< _Nb2 > &) template std::basic_istream< _CharT, _Traits > & operator>> (std::basic_istream< _CharT, _Traits > &, bitset< _Nb2 > &) class reference struct std::hash< bitset > Detailed Description template class std::bitset< _Nb >"The bitset class represents a fixed-size sequence of bits. (Note that bitset does not meet the formal requirements of a container. Mainly, it lacks iterators.) The template argument, Nb, may be any non-negative number, specifying the number of bits (e.g., '0', '12', '1024*1024'). In the general unoptimized case, storage is allocated in word-sized blocks. Let B be the number of bits in a word, then (Nb+(B-1))/B words will be used for storage. B - NbB bits are unused. (They are the high- order bits in the highest word.) It is a class invariant that those unused bits are always zero. If you think of bitset as a simple array of bits, be aware that your mental picture is reversed: a bitset behaves the same way as bits in integers do, with the bit at index 0 in the least significant / right- hand position, and the bit at index Nb-1 in the most significant / left-hand position. Thus, unlike other containers, a bitset's index counts from right to left, to put it very loosely. This behavior is preserved when translating to and from strings. For example, the first line of the following program probably prints b('a') is 0001100001 on a modern ASCII system. #include #include #include using namespace std; int main() { long a = 'a'; bitset<10> b(a); cout << "b('a') is " << b << endl; ostringstream s; s << b; string str = s.str(); cout << "index 3 in the string is " << str[3] << " but\n" << "index 3 in the bitset is " << b[3] << endl; } Also see: https://gcc.gnu.org/onlinedocs/libstdc++/manual/ext_containers.html for a description of extensions. Most of the actual code isn't contained in bitset<> itself, but in the base class _Base_bitset. The base class works with whole words, not with individual bits. This allows us to specialize _Base_bitset for the important special case where the bitset is only a single word. Extra confusion can result due to the fact that the storage for _Base_bitset is a regular array, and is indexed as such. This is carefully encapsulated. Constructor & Destructor Documentation template constexpr std::bitset< _Nb >::bitset () [inline], [constexpr], [noexcept] All bits set to zero. template constexpr std::bitset< _Nb >::bitset (unsigned long long __val) [inline], [constexpr], [noexcept] Initial bits bitwise-copied from a single word (others set to zero). template template constexpr std::bitset< _Nb >::bitset (const std::basic_string< _CharT, _Traits, _Alloc > & __s, size_t __position = 0) [inline], [explicit], [constexpr] Use a subset of a string. Parameters __s A string of 0 and 1 characters. __position Index of the first character in __s to use; defaults to zero. Exceptions std::out_of_range If pos is bigger the size of __s. std::invalid_argument If a character appears in the string which is neither 0 nor 1. References std::forward(). template template constexpr std::bitset< _Nb >::bitset (const std::basic_string< _CharT, _Traits, _Alloc > & __s, size_t __position, size_t __n) [inline], [constexpr] Use a subset of a string. Parameters __s A string of 0 and 1 characters. __position Index of the first character in __s to use. __n The number of characters to copy. Exceptions std::out_of_range If __position is bigger the size of __s. std::invalid_argument If a character appears in the string which is neither 0 nor 1. References std::forward(). template template constexpr std::bitset< _Nb >::bitset (const _CharT * __str, typename __bitset< _Nb >::__string< _CharT >::size_type __n = __bitset< _Nb >::__string<_CharT>::npos, _CharT __zero = _CharT('0'), _CharT __one = _CharT('1')) [inline], [explicit], [constexpr] Construct from a character array. Parameters __str An array of characters zero and one. __n The number of characters to use. __zero The character corresponding to the value 0. __one The character corresponding to the value 1. Exceptions std::invalid_argument If a character appears in the string which is neither __zero nor __one. References std::forward(). Member Function Documentation template constexpr bool std::bitset< _Nb >::all () const [inline], [constexpr], [noexcept] Tests whether all the bits are on. Returns True if all the bits are set. References std::forward(). template constexpr bool std::bitset< _Nb >::any () const [inline], [constexpr], [noexcept] Tests whether any of the bits are on. Returns True if at least one bit is set. template constexpr size_t std::bitset< _Nb >::count () const [inline], [constexpr], [noexcept] Returns the number of bits which are set. template constexpr bitset< _Nb > & std::bitset< _Nb >::flip () [inline], [constexpr], [noexcept] Toggles every bit to its opposite value. template constexpr bitset< _Nb > & std::bitset< _Nb >::flip (size_t __position) [inline], [constexpr] Toggles a given bit to its opposite value. Parameters __position The index of the bit. Exceptions std::out_of_range If pos is bigger the size of the set. References std::forward(). template constexpr bool std::bitset< _Nb >::none () const [inline], [constexpr], [noexcept] Tests whether any of the bits are on. Returns True if none of the bits are set. template constexpr bitset< _Nb > & std::bitset< _Nb >::operator&= (const bitset< _Nb > & __rhs) [inline], [constexpr], [noexcept] Operations on bitsets. Parameters __rhs A same-sized bitset. These should be self-explanatory. References std::forward(). template constexpr bitset< _Nb > std::bitset< _Nb >::operator<< (size_t __position) const [inline], [constexpr], [noexcept] Self-explanatory. References std::forward(). template constexpr bitset< _Nb > & std::bitset< _Nb >::operator<<= (size_t __position) [inline], [constexpr], [noexcept] Operations on bitsets. Parameters __position The number of places to shift. These should be self-explanatory. References std::forward(). template constexpr bool std::bitset< _Nb >::operator== (const bitset< _Nb > & __rhs) const [inline], [constexpr], [noexcept] These comparisons for equality/inequality are, well, bitwise. References std::forward(). template constexpr bitset< _Nb > std::bitset< _Nb >::operator>> (size_t __position) const [inline], [constexpr], [noexcept] Self-explanatory. References std::forward(). template constexpr bitset< _Nb > & std::bitset< _Nb >::operator>>= (size_t __position) [inline], [constexpr], [noexcept] Operations on bitsets. Parameters __position The number of places to shift. These should be self-explanatory. References std::forward(). template constexpr reference std::bitset< _Nb >::operator[] (size_t __position) [inline], [constexpr] Array-indexing support. Parameters __position Index into the bitset. Returns A bool for a const bitset. For non-const bitsets, an instance of the reference proxy class. Note These operators do no range checking and throw no exceptions, as required by DR 11 to the standard. _GLIBCXX_RESOLVE_LIB_DEFECTS Note that this implementation already resolves DR 11 (items 1 and 2), but does not do the range-checking required by that DR's resolution. -pme The DR has since been changed: range-checking is a precondition (users' responsibility), and these functions must not throw. -pme References std::forward(). template constexpr bool std::bitset< _Nb >::operator[] (size_t __position) const [inline], [constexpr] Array-indexing support. Parameters __position Index into the bitset. Returns A bool for a const bitset. For non-const bitsets, an instance of the reference proxy class. Note These operators do no range checking and throw no exceptions, as required by DR 11 to the standard. _GLIBCXX_RESOLVE_LIB_DEFECTS Note that this implementation already resolves DR 11 (items 1 and 2), but does not do the range-checking required by that DR's resolution. -pme The DR has since been changed: range-checking is a precondition (users' responsibility), and these functions must not throw. -pme References std::forward(). template constexpr bitset< _Nb > & std::bitset< _Nb >::operator^= (const bitset< _Nb > & __rhs) [inline], [constexpr], [noexcept] Operations on bitsets. Parameters __rhs A same-sized bitset. These should be self-explanatory. References std::forward(). template constexpr bitset< _Nb > & std::bitset< _Nb >::operator|= (const bitset< _Nb > & __rhs) [inline], [constexpr], [noexcept] Operations on bitsets. Parameters __rhs A same-sized bitset. These should be self-explanatory. References std::forward(). template constexpr bitset< _Nb > std::bitset< _Nb >::operator~ () const [inline], [constexpr], [noexcept] See the no-argument flip(). References std::forward(). template constexpr bitset< _Nb > & std::bitset< _Nb >::reset () [inline], [constexpr], [noexcept] Sets every bit to false. template constexpr bitset< _Nb > & std::bitset< _Nb >::reset (size_t __position) [inline], [constexpr] Sets a given bit to false. Parameters __position The index of the bit. Exceptions std::out_of_range If pos is bigger the size of the set. Same as writing set(pos,false). References std::forward(). template constexpr bitset< _Nb > & std::bitset< _Nb >::set () [inline], [constexpr], [noexcept] Sets every bit to true. template constexpr bitset< _Nb > & std::bitset< _Nb >::set (size_t __position, bool __val = true) [inline], [constexpr] Sets a given bit to a particular value. Parameters __position The index of the bit. __val Either true or false, defaults to true. Exceptions std::out_of_range If pos is bigger the size of the set. References std::forward(). template constexpr size_t std::bitset< _Nb >::size () const [inline], [constexpr], [noexcept] Returns the total number of bits. References std::forward(). template constexpr bool std::bitset< _Nb >::test (size_t __position) const [inline], [constexpr] Tests the value of a bit. Parameters __position The index of a bit. Returns The value at pos. Exceptions std::out_of_range If pos is bigger the size of the set. References std::forward(). template template constexpr std::basic_string< _CharT, _Traits, _Alloc > std::bitset< _Nb >::to_string () const [inline], [constexpr] Returns a character interpretation of the bitset. Returns The string equivalent of the bits. Note the ordering of the bits: decreasing character positions correspond to increasing bit positions (see the main class notes for an example). template constexpr unsigned long std::bitset< _Nb >::to_ulong () const [inline], [constexpr] Returns a numerical interpretation of the bitset. Returns The integral equivalent of the bits. Exceptions std::overflow_error If there are too many bits to be represented in an unsigned long. Author Generated automatically by Doxygen for libstdc++ from the source code. libstdc++ std::bitset< _Nb >(3)