std::bitset::bitset

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Utilities library

Type support (basic types, RTTI, type traits)

Dynamic memory management

Error handling

Program utilities

Variadic functions

Date and time

Function objects

initializer_list (C++11)

bitset

hash (C++11)

Relational operators

rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=

Pairs and tuples

pair

tuple (C++11)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

Swap, forward and move

swap

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

declval (C++11)

 

std::bitset

Member types

bitset::reference

Member functions

bitset::bitset

bitset::operator==bitset::operator!=

Element access

bitset::operator[]

bitset::test

bitset::allbitset::anybitset::none (C++11)

bitset::count

Capacity

bitset::size

Modifiers

bitset::operator&=bitset::operator|=bitset::operator^=bitset::operator~

bitset::operator<<=bitset::operator>>=bitset::operator<<bitset::operator>>

bitset::set

bitset::reset

bitset::flip

Conversions

bitset::to_string

bitset::to_ulong

bitset::to_ullong (C++11)

Non-member functions

operator&operator|operator^

operator<<operator>>

Helper classes

std::hash (C++11)

 

constexpr bitset() noexcept;	(1)
constexpr bitset( unsigned long long val ) noexcept;	(2)
	(3)
template< class CharT, class Traits, class Alloc > explicit bitset( const std::basic_string<CharT,Traits,Alloc>& str,                  typename std::basic_string<CharT,Traits,Alloc>::size_type pos = 0,                  typename std::basic_string<CharT,Traits,Alloc>::size_type n =                      std::basic_string<CharT,Traits,Alloc>::npos);			(until C++11)
template< class CharT, class Traits, class Alloc > explicit bitset( const std::basic_string<CharT,Traits,Alloc>& str,                  typename std::basic_string<CharT,Traits,Alloc>::size_type pos = 0,                  typename std::basic_string<CharT,Traits,Alloc>::size_type n =                      std::basic_string<CharT,Traits,Alloc>::npos,                  CharT zero = CharT(’0’),                  CharT one = CharT(’1’));			(since C++11)
template< class CharT > explicit 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’));		(4)	(since C++11)

Constructs a new bitset from one of several optional data sources:

1) Default constructor. Constructs a bitset with all bits set to zero.

2) Constructs a bitset, initializing the first (rightmost, least significant) M bit positions to the corresponding bit values of val, where M is the smaller of the number of bits in an unsigned long long and the number of bits N in the bitset being constructed. If M is less than N (the bitset is longer than 64 bits, for typical implementations of unsigned long long), the remaining bit positions are initialized to zeroes.

3) Constructs a bitset using the characters in the std::basic_string str. An optional starting position pos and length n can be provided, as well as characters denoting alternate values for set (one) and unset (zero) bits. Traits::eq() is used to compare the character values.

The effective length of the initializing string is min(n, str.size() - pos).

If pos > str.size(), this constructor throws std::out_of_range. If any characters examined in str are not zero or one, it throws std::invalid_argument.

4) Similar to (3), but uses a CharT* instead of a std::basic_string. Equivalent to bitset(n == basic_string<charT>::npos ? basic_string<charT>(str) : basic_string<charT>(str, n), 0, n, zero, one)

Parameters

val	-	number used to initialize the bitset
str	-	string used to initialize the bitset
pos	-	a starting offset into str
n	-	number of characters to use from str
one	-	alternate character for set bits in str
zero	-	alternate character for unset bits in str

Exceptions

1. none

2. none

3. std::out_of_range if pos > str.size(), std::invalid_argument if any character is not one or zero

4. std::invalid_argument if any character is not one or zero

Example

Run this code

#include <bitset>
#include <string>
#include <iostream>
#include <climits>
 
int main() 
{
    // empty constructor
    std::bitset<8> b1; // [0,0,0,0,0,0,0,0]
 
    // unsigned long long constructor
    std::bitset<8> b2(42);          // [0,0,1,0,1,0,1,0]
    std::bitset<70> bl(ULLONG_MAX); // [0,0,0,0,0,0,1,1,1,...,1,1,1]
    std::bitset<8> bs(0xfff0);      // [1,1,1,1,0,0,0,0]
 
    // string constructor
    std::string bit_string = "110010";
    std::bitset<8> b3(bit_string);       // [0,0,1,1,0,0,1,0]
    std::bitset<8> b4(bit_string, 2);    // [0,0,0,0,0,0,1,0]
    std::bitset<8> b5(bit_string, 2, 3); // [0,0,0,0,0,0,0,1]
 
    // string constructor using custom zero/one digits
    std::string alpha_bit_string = "aBaaBBaB";
    std::bitset<8> b6(alpha_bit_string, 0, alpha_bit_string.size(),
                      'a', 'B');         // [0,1,0,0,1,1,0,1]
 
    // char* constructor using custom digits
    std::bitset<8> b7("XXXXYYYY", 8, 'X', 'Y'); // [0,0,0,0,1,1,1,1]
 
    std::cout << b1 << '\n' << b2 << '\n' << bl << '\n' << bs << '\n'
              << b3 << '\n' << b4 << '\n' << b5 << '\n' << b6 << '\n'
              << b7 << '\n';
}

Output:

00000000
00101010
0000001111111111111111111111111111111111111111111111111111111111111111
11110000
00110010
00000010
00000001
01001101
00001111

See also

set	sets bits to true or given value (public member function)
reset	sets bits to false (public member function)