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++/ext/sgiexts.html#ch23 for a description of extensions.
Definition at line 645 of file bitset.
bitset | ( | unsigned long | __val | ) | [inline] |
bitset | ( | const std::basic_string< _CharT, _Traits, _Alloc > & | __s, | |
size_t | __position = 0 | |||
) | [inline, explicit] |
Use a subset of a string.
s | A string of '0' and '1' characters. | |
position | Index of the first character in s to use; defaults to zero. |
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'. |
Definition at line 754 of file bitset.
References bitset::_M_copy_from_string(), and basic_string::size().
bitset | ( | const std::basic_string< _CharT, _Traits, _Alloc > & | __s, | |
size_t | __position, | |||
size_t | __n | |||
) | [inline] |
Use a subset of a string.
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. |
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'. |
Definition at line 775 of file bitset.
References bitset::_M_copy_from_string(), and basic_string::size().
bool any | ( | ) | const [inline] |
Tests whether any of the bits are on.
Definition at line 1099 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_is_any().
size_t count | ( | ) | const [inline] |
Returns the number of bits which are set.
Definition at line 1061 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_count().
bitset<_Nb>& flip | ( | size_t | __position | ) | [inline] |
Toggles a given bit to its opposite value.
position | The index of the bit. |
std::out_of_range | If pos is bigger the size of the set. |
Definition at line 960 of file bitset.
References bitset::_Unchecked_flip().
bitset<_Nb>& flip | ( | ) | [inline] |
Toggles every bit to its opposite value.
Definition at line 947 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_flip().
bool none | ( | ) | const [inline] |
Tests whether any of the bits are on.
Definition at line 1107 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_is_any().
Operations on bitsets.
rhs | A same-sized bitset. |
Definition at line 794 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_and().
bitset<_Nb> operator<< | ( | size_t | __position | ) | const [inline] |
bitset<_Nb>& operator<<= | ( | size_t | __position | ) | [inline] |
Operations on bitsets.
position | The number of places to shift. |
Definition at line 823 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_left_shift(), and _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_reset().
bool operator== | ( | const bitset< _Nb > & | __rhs | ) | const [inline] |
These comparisons for equality/inequality are, well, bitwise.
Definition at line 1072 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_is_equal().
bitset<_Nb> operator>> | ( | size_t | __position | ) | const [inline] |
bitset<_Nb>& operator>>= | ( | size_t | __position | ) | [inline] |
Operations on bitsets.
position | The number of places to shift. |
Definition at line 836 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_reset(), and _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_right_shift().
reference operator[] | ( | size_t | __position | ) | [inline] |
Array-indexing support.
position | Index into the bitset. |
Definition at line 990 of file bitset.
References bitset::reference.
Operations on bitsets.
rhs | A same-sized bitset. |
Definition at line 808 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_xor().
Operations on bitsets.
rhs | A same-sized bitset. |
Definition at line 801 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_or().
bitset<_Nb> operator~ | ( | ) | const [inline] |
bitset<_Nb>& reset | ( | size_t | __position | ) | [inline] |
Sets a given bit to false.
position | The index of the bit. |
std::out_of_range | If pos is bigger the size of the set. |
set(pos,false)
.
Definition at line 936 of file bitset.
References bitset::_Unchecked_reset().
bitset<_Nb>& reset | ( | ) | [inline] |
Sets every bit to false.
Definition at line 922 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_reset().
Referenced by bitset::_M_copy_from_string().
Sets a given bit to a particular value.
position | The index of the bit. | |
val | Either true or false, defaults to true. |
std::out_of_range | If pos is bigger the size of the set. |
Definition at line 911 of file bitset.
References __gnu_cxx::__val, and bitset::_Unchecked_set().
Sets every bit to true.
Definition at line 897 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_set().
Referenced by bitset::_M_copy_from_string().
size_t size | ( | ) | const [inline] |
bool test | ( | size_t | __position | ) | const [inline] |
Tests the value of a bit.
position | The index of a bit. |
std::out_of_range | If pos is bigger the size of the set. |
Definition at line 1087 of file bitset.
References bitset::_Unchecked_test().
std::basic_string<_CharT, _Traits, _Alloc> to_string | ( | ) | const [inline] |
Retuns a character interpretation of the bitset.
Definition at line 1018 of file bitset.
References bitset::_M_copy_to_string().
unsigned long to_ulong | ( | ) | const [inline] |
Retuns a numerical interpretation of the bitset.
std::overflow_error | If there are too many bits to be represented in an unsigned long . |
Definition at line 1005 of file bitset.
References _Base_bitset< _GLIBCXX_BITSET_WORDS(_Nb)>::_M_do_to_ulong().