libstdc++
std::bitset< _Nb > Class Template Reference
Inheritance diagram for std::bitset< _Nb >:
[legend]

Classes

class  reference
 

Public Member Functions

constexpr bitset () noexcept
 
template<typename _CharT >
 bitset (const _CharT *__str, typename std::basic_string< _CharT >::size_type __n=std::basic_string< _CharT >::npos, _CharT __zero=_CharT('0'), _CharT __one=_CharT('1'))
 
template<class _CharT , class _Traits , class _Alloc >
 bitset (const std::basic_string< _CharT, _Traits, _Alloc > &__s, size_t __position, size_t __n)
 
template<class _CharT , class _Traits , class _Alloc >
 bitset (const std::basic_string< _CharT, _Traits, _Alloc > &__s, size_t __position, size_t __n, _CharT __zero, _CharT __one=_CharT('1'))
 
template<class _CharT , class _Traits , class _Alloc >
 bitset (const std::basic_string< _CharT, _Traits, _Alloc > &__s, size_t __position=0)
 
constexpr bitset (unsigned long long __val) noexcept
 
size_t _Find_first () const noexcept
 
size_t _Find_next (size_t __prev) const noexcept
 
template<class _CharT , class _Traits >
void _M_copy_from_ptr (const _CharT *, size_t, size_t, size_t, _CharT, _CharT)
 
template<class _CharT , class _Traits , class _Alloc >
void _M_copy_from_string (const std::basic_string< _CharT, _Traits, _Alloc > &__s, size_t __pos, size_t __n)
 
template<class _CharT , class _Traits , class _Alloc >
void _M_copy_from_string (const std::basic_string< _CharT, _Traits, _Alloc > &__s, size_t __pos, size_t __n, _CharT __zero, _CharT __one)
 
template<class _CharT , class _Traits , class _Alloc >
void _M_copy_to_string (std::basic_string< _CharT, _Traits, _Alloc > &, _CharT, _CharT) const
 
template<class _CharT , class _Traits , class _Alloc >
void _M_copy_to_string (std::basic_string< _CharT, _Traits, _Alloc > &__s) const
 
bool all () const noexcept
 
bool any () const noexcept
 
size_t count () const noexcept
 
bitset< _Nb > & flip () noexcept
 
bitset< _Nb > & flip (size_t __position)
 
bool none () const noexcept
 
bitset< _Nb > operator~ () const noexcept
 
bitset< _Nb > & reset () noexcept
 
bitset< _Nb > & reset (size_t __position)
 
bitset< _Nb > & set () noexcept
 
bitset< _Nb > & set (size_t __position, bool __val=true)
 
constexpr size_t size () const noexcept
 
bool test (size_t __position) const
 
template<class _CharT , class _Traits , class _Alloc >
std::basic_string< _CharT, _Traits, _Alloc > to_string () const
 
template<class _CharT , class _Traits >
std::basic_string< _CharT, _Traits, std::allocator< _CharT > > to_string () const
 
template<class _CharT >
std::basic_string< _CharT, std::char_traits< _CharT >, std::allocator< _CharT > > to_string () const
 
std::basic_string< char, std::char_traits< char >, std::allocator< char > > to_string () const
 
template<class _CharT , class _Traits , class _Alloc >
std::basic_string< _CharT, _Traits, _Alloc > to_string (_CharT __zero, _CharT __one=_CharT('1')) const
 
template<class _CharT , class _Traits >
std::basic_string< _CharT, _Traits, std::allocator< _CharT > > to_string (_CharT __zero, _CharT __one=_CharT('1')) const
 
template<class _CharT >
std::basic_string< _CharT, std::char_traits< _CharT >, std::allocator< _CharT > > to_string (_CharT __zero, _CharT __one=_CharT('1')) const
 
std::basic_string< char, std::char_traits< char >, std::allocator< char > > to_string (char __zero, char __one='1') const
 
unsigned long long to_ullong () const
 
unsigned long to_ulong () const
 
bitset< _Nb > & operator&= (const bitset< _Nb > &__rhs) noexcept
 
bitset< _Nb > & operator|= (const bitset< _Nb > &__rhs) noexcept
 
bitset< _Nb > & operator^= (const bitset< _Nb > &__rhs) noexcept
 
bitset< _Nb > & operator<<= (size_t __position) noexcept
 
bitset< _Nb > & operator>>= (size_t __position) noexcept
 
bitset< _Nb > & _Unchecked_set (size_t __pos) noexcept
 
bitset< _Nb > & _Unchecked_set (size_t __pos, int __val) noexcept
 
bitset< _Nb > & _Unchecked_reset (size_t __pos) noexcept
 
bitset< _Nb > & _Unchecked_flip (size_t __pos) noexcept
 
constexpr bool _Unchecked_test (size_t __pos) const noexcept
 
reference operator[] (size_t __position)
 
constexpr bool operator[] (size_t __position) const
 
bool operator== (const bitset< _Nb > &__rhs) const noexcept
 
bool operator!= (const bitset< _Nb > &__rhs) const noexcept
 
bitset< _Nb > operator<< (size_t __position) const noexcept
 
bitset< _Nb > operator>> (size_t __position) const noexcept
 

Friends

class reference
 
struct std::hash< bitset >
 

Detailed Description

template<size_t _Nb>
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 <bitset>
#include <iostream>
#include <sstream>
using namespace std;
int main()
{
long a = 'a';
bitset<10> b(a);
cout << "b('a') is " << b << endl;
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;
}
basic_ostringstream< char > ostringstream
Class for char output memory streams.
Definition: iosfwd:153
ISO C++ entities toplevel namespace is std.
basic_ostream< _CharT, _Traits > & endl(basic_ostream< _CharT, _Traits > &__os)
Write a newline and flush the stream.
Definition: ostream:675
ostream cout
Linked to standard input.

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.

Definition at line 751 of file bitset.

Constructor & Destructor Documentation

◆ bitset() [1/5]

template<size_t _Nb>
constexpr std::bitset< _Nb >::bitset ( )
inlineconstexprnoexcept

All bits set to zero.

Definition at line 869 of file bitset.

◆ bitset() [2/5]

template<size_t _Nb>
constexpr std::bitset< _Nb >::bitset ( unsigned long long  __val)
inlineconstexprnoexcept

Initial bits bitwise-copied from a single word (others set to zero).

Definition at line 874 of file bitset.

◆ bitset() [3/5]

template<size_t _Nb>
template<class _CharT , class _Traits , class _Alloc >
std::bitset< _Nb >::bitset ( const std::basic_string< _CharT, _Traits, _Alloc > &  __s,
size_t  __position = 0 
)
inlineexplicit

Use a subset of a string.

Parameters
__sA string of 0 and 1 characters.
__positionIndex of the first character in __s to use; defaults to zero.
Exceptions
std::out_of_rangeIf pos is bigger the size of __s.
std::invalid_argumentIf a character appears in the string which is neither 0 nor 1.

Definition at line 893 of file bitset.

◆ bitset() [4/5]

template<size_t _Nb>
template<class _CharT , class _Traits , class _Alloc >
std::bitset< _Nb >::bitset ( const std::basic_string< _CharT, _Traits, _Alloc > &  __s,
size_t  __position,
size_t  __n 
)
inline

Use a subset of a string.

Parameters
__sA string of 0 and 1 characters.
__positionIndex of the first character in __s to use.
__nThe number of characters to copy.
Exceptions
std::out_of_rangeIf __position is bigger the size of __s.
std::invalid_argumentIf a character appears in the string which is neither 0 nor 1.

Definition at line 914 of file bitset.

◆ bitset() [5/5]

template<size_t _Nb>
template<typename _CharT >
std::bitset< _Nb >::bitset ( const _CharT *  __str,
typename std::basic_string< _CharT >::size_type  __n = std::basic_string<_CharT>::npos,
_CharT  __zero = _CharT('0'),
_CharT  __one = _CharT('1') 
)
inlineexplicit

Construct from a character array.

Parameters
__strAn array of characters zero and one.
__nThe number of characters to use.
__zeroThe character corresponding to the value 0.
__oneThe character corresponding to the value 1.
Exceptions
std::invalid_argumentIf a character appears in the string which is neither __zero nor __one.

Definition at line 946 of file bitset.

Member Function Documentation

◆ all()

template<size_t _Nb>
bool std::bitset< _Nb >::all ( ) const
inlinenoexcept

Tests whether all the bits are on.

Returns
True if all the bits are set.

Definition at line 1336 of file bitset.

◆ any()

template<size_t _Nb>
bool std::bitset< _Nb >::any ( ) const
inlinenoexcept

Tests whether any of the bits are on.

Returns
True if at least one bit is set.

Definition at line 1344 of file bitset.

◆ count()

template<size_t _Nb>
size_t std::bitset< _Nb >::count ( ) const
inlinenoexcept

Returns the number of bits which are set.

Definition at line 1295 of file bitset.

◆ flip() [1/2]

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::flip ( )
inlinenoexcept

Toggles every bit to its opposite value.

Definition at line 1123 of file bitset.

Referenced by std::bitset< _Nb >::operator~().

◆ flip() [2/2]

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::flip ( size_t  __position)
inline

Toggles a given bit to its opposite value.

Parameters
__positionThe index of the bit.
Exceptions
std::out_of_rangeIf pos is bigger the size of the set.

Definition at line 1136 of file bitset.

◆ none()

template<size_t _Nb>
bool std::bitset< _Nb >::none ( ) const
inlinenoexcept

Tests whether any of the bits are on.

Returns
True if none of the bits are set.

Definition at line 1352 of file bitset.

◆ operator!=()

template<size_t _Nb>
bool std::bitset< _Nb >::operator!= ( const bitset< _Nb > &  __rhs) const
inlinenoexcept

These comparisons for equality/inequality are, well, bitwise.

Definition at line 1311 of file bitset.

◆ operator&=()

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::operator&= ( const bitset< _Nb > &  __rhs)
inlinenoexcept

Operations on bitsets.

Parameters
__rhsA same-sized bitset.

These should be self-explanatory.

Definition at line 972 of file bitset.

◆ operator<<()

template<size_t _Nb>
bitset<_Nb> std::bitset< _Nb >::operator<< ( size_t  __position) const
inlinenoexcept

Self-explanatory.

Definition at line 1352 of file bitset.

◆ operator<<=()

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::operator<<= ( size_t  __position)
inlinenoexcept

Operations on bitsets.

Parameters
__positionThe number of places to shift.

These should be self-explanatory.

Definition at line 986 of file bitset.

◆ operator==()

template<size_t _Nb>
bool std::bitset< _Nb >::operator== ( const bitset< _Nb > &  __rhs) const
inlinenoexcept

These comparisons for equality/inequality are, well, bitwise.

Definition at line 1306 of file bitset.

◆ operator>>()

template<size_t _Nb>
bitset<_Nb> std::bitset< _Nb >::operator>> ( size_t  __position) const
inlinenoexcept

Self-explanatory.

Definition at line 1362 of file bitset.

◆ operator>>=()

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::operator>>= ( size_t  __position)
inlinenoexcept

Operations on bitsets.

Parameters
__positionThe number of places to shift.

These should be self-explanatory.

Definition at line 1014 of file bitset.

◆ operator[]() [1/2]

template<size_t _Nb>
reference std::bitset< _Nb >::operator[] ( size_t  __position)
inline

Array-indexing support.

Parameters
__positionIndex 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

Definition at line 1163 of file bitset.

◆ operator[]() [2/2]

template<size_t _Nb>
constexpr bool std::bitset< _Nb >::operator[] ( size_t  __position) const
inlineconstexpr

Array-indexing support.

Parameters
__positionIndex 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

Definition at line 1167 of file bitset.

◆ operator^=()

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::operator^= ( const bitset< _Nb > &  __rhs)
inlinenoexcept

Operations on bitsets.

Parameters
__rhsA same-sized bitset.

These should be self-explanatory.

Definition at line 986 of file bitset.

◆ operator|=()

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::operator|= ( const bitset< _Nb > &  __rhs)
inlinenoexcept

Operations on bitsets.

Parameters
__rhsA same-sized bitset.

These should be self-explanatory.

Definition at line 979 of file bitset.

◆ operator~()

template<size_t _Nb>
bitset<_Nb> std::bitset< _Nb >::operator~ ( ) const
inlinenoexcept

See the no-argument flip().

Definition at line 1144 of file bitset.

References std::bitset< _Nb >::flip().

◆ reset() [1/2]

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::reset ( )
inlinenoexcept

Sets every bit to false.

Definition at line 1099 of file bitset.

◆ reset() [2/2]

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::reset ( size_t  __position)
inline

Sets a given bit to false.

Parameters
__positionThe index of the bit.
Exceptions
std::out_of_rangeIf pos is bigger the size of the set.

Same as writing set(pos,false).

Definition at line 1113 of file bitset.

◆ set() [1/2]

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::set ( )
inlinenoexcept

Sets every bit to true.

Definition at line 1075 of file bitset.

◆ set() [2/2]

template<size_t _Nb>
bitset<_Nb>& std::bitset< _Nb >::set ( size_t  __position,
bool  __val = true 
)
inline

Sets a given bit to a particular value.

Parameters
__positionThe index of the bit.
__valEither true or false, defaults to true.
Exceptions
std::out_of_rangeIf pos is bigger the size of the set.

Definition at line 1089 of file bitset.

◆ size()

template<size_t _Nb>
constexpr size_t std::bitset< _Nb >::size ( ) const
inlineconstexprnoexcept

Returns the total number of bits.

Definition at line 1300 of file bitset.

◆ test()

template<size_t _Nb>
bool std::bitset< _Nb >::test ( size_t  __position) const
inline

Tests the value of a bit.

Parameters
__positionThe index of a bit.
Returns
The value at pos.
Exceptions
std::out_of_rangeIf pos is bigger the size of the set.

Definition at line 1323 of file bitset.

◆ to_string()

template<size_t _Nb>
template<class _CharT , class _Traits , class _Alloc >
std::basic_string<_CharT, _Traits, _Alloc> std::bitset< _Nb >::to_string ( ) const
inline

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).

Definition at line 1197 of file bitset.

◆ to_ulong()

template<size_t _Nb>
unsigned long std::bitset< _Nb >::to_ulong ( ) const
inline

Returns a numerical interpretation of the bitset.

Returns
The integral equivalent of the bits.
Exceptions
std::overflow_errorIf there are too many bits to be represented in an unsigned long.

Definition at line 1178 of file bitset.


The documentation for this class was generated from the following file: