std::bitset< _Nb > Class Template Reference
[Containers]
List of all members.
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;
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: http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt12ch33s02.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 651 of file bitset.
Public Member Functions
- size_t _Find_first () const
- size_t _Find_next (size_t __prev) const
-
template<class _CharT, class _Traits, class _Alloc> void _M_copy_from_string (const std::basic_string< _CharT, _Traits, _Alloc > &__s, size_t, size_t)
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template<class _CharT, class _Traits, class _Alloc> void _M_copy_to_string (std::basic_string< _CharT, _Traits, _Alloc > &) const
- bool all () const
- bool any () const
- 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=0)
- bitset (unsigned long __val)
- bitset ()
- size_t count () const
- bitset< _Nb > & flip (size_t __position)
- bitset< _Nb > & flip ()
- bool none () const
- bitset< _Nb > operator~ () const
- bitset< _Nb > & reset (size_t __position)
- bitset< _Nb > & reset ()
- bitset< _Nb > & set (size_t __position, bool __val=true)
- bitset< _Nb > & set ()
- size_t size () const
- bool test (size_t __position) const
-
std::basic_string< char,
std::char_traits< char >
, std::allocator< char > > to_string () const
-
template<class _CharT> std::basic_string< _CharT,
std::char_traits< _CharT >
, std::allocator< _CharT > > to_string () const
-
template<class _CharT, class _Traits> std::basic_string< _CharT,
_Traits, std::allocator
< _CharT > > to_string () const
- template<class _CharT, class _Traits, class _Alloc> std::basic_string< _CharT,
_Traits, _Alloc > to_string () const
- unsigned long to_ulong () const
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Friends
Classes
Constructor & Destructor Documentation
All bits set to zero.
Definition at line 741 of file bitset.
Initial bits bitwise-copied from a single word (others set to zero).
Definition at line 745 of file bitset.
template<size_t _Nb>
template<class _CharT, class _Traits, class _Alloc>
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:
-
Definition at line 760 of file bitset.
template<size_t _Nb>
template<class _CharT, class _Traits, class _Alloc>
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:
-
Definition at line 781 of file bitset.
Member Function Documentation
These versions of single-bit set, reset, flip, and test are extensions from the SGI version. They do no range checking.
Definition at line 886 of file bitset.
These versions of single-bit set, reset, flip, and test are extensions from the SGI version. They do no range checking.
Definition at line 879 of file bitset.
These versions of single-bit set, reset, flip, and test are extensions from the SGI version. They do no range checking.
Definition at line 869 of file bitset.
template<size_t _Nb>
bool std::bitset< _Nb >::_Unchecked_test |
( |
size_t |
__pos |
) |
const [inline] |
These versions of single-bit set, reset, flip, and test are extensions from the SGI version. They do no range checking.
Definition at line 893 of file bitset.
Tests whether all the bits are on.
- Returns:
- True if all the bits are set.
Definition at line 1105 of file bitset.
Tests whether any of the bits are on.
- Returns:
- True if at least one bit is set.
Definition at line 1113 of file bitset.
Returns the number of bits which are set.
Definition at line 1065 of file bitset.
Toggles a given bit to its opposite value.
- Parameters:
-
| position | The index of the bit. |
- Exceptions:
-
Definition at line 966 of file bitset.
Toggles every bit to its opposite value.
Definition at line 953 of file bitset.
Tests whether any of the bits are on.
- Returns:
- True if none of the bits are set.
Definition at line 1121 of file bitset.
Operations on bitsets.
- Parameters:
-
These should be self-explanatory.
Definition at line 800 of file bitset.
These comparisons for equality/inequality are, well, bitwise.
Definition at line 1080 of file bitset.
Self-explanatory.
Definition at line 1127 of file bitset.
Operations on bitsets.
- Parameters:
-
| position | The number of places to shift. |
These should be self-explanatory.
Definition at line 829 of file bitset.
These comparisons for equality/inequality are, well, bitwise.
Definition at line 1076 of file bitset.
Self-explanatory.
Definition at line 1131 of file bitset.
Operations on bitsets.
- Parameters:
-
| position | The number of places to shift. |
These should be self-explanatory.
Definition at line 842 of file bitset.
template<size_t _Nb>
bool std::bitset< _Nb >::operator[] |
( |
size_t |
__position |
) |
const [inline] |
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
Definition at line 998 of file bitset.
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
Definition at line 994 of file bitset.
Operations on bitsets.
- Parameters:
-
These should be self-explanatory.
Definition at line 814 of file bitset.
Operations on bitsets.
- Parameters:
-
These should be self-explanatory.
Definition at line 807 of file bitset.
Sets a given bit to false.
- Parameters:
-
| position | The index of the bit. |
- Exceptions:
-
Same as writing
set(pos,false)
.
Definition at line 942 of file bitset.
Sets every bit to false.
Definition at line 928 of file bitset.
Sets a given bit to a particular value.
- Parameters:
-
| position | The index of the bit. |
| val | Either true or false, defaults to true. |
- Exceptions:
-
Definition at line 917 of file bitset.
Sets every bit to true.
Definition at line 903 of file bitset.
Returns the total number of bits.
Definition at line 1070 of file bitset.
template<size_t _Nb>
bool std::bitset< _Nb >::test |
( |
size_t |
__position |
) |
const [inline] |
Tests the value of a bit.
- Parameters:
-
| position | The index of a bit. |
- Returns:
- The value at pos.
- Exceptions:
-
Definition at line 1091 of file bitset.
template<size_t _Nb>
template<class _CharT, class _Traits, class _Alloc>
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 1022 of file bitset.
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:
-
Definition at line 1009 of file bitset.
The documentation for this class was generated from the following file: