std::bitset::bitset (3) Linux Manual Page
std::bitset<N>::bitset – std::bitset<N>::bitset
Synopsis
bitset();
(until C++ 11)
constexpr bitset() noexcept;
(since C++ 11)
bitset(unsigned long val);
(until C++ 11)
constexpr bitset(unsigned long long val) noexcept;
(since 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(until C++ 11)
pos = 0,
typename std::basic_string<CharT, Traits, Alloc>::size_type
n = std::basic_string<CharT, Traits, Alloc>::npos);
template <class CharT, class Traits, class Alloc>
explicit bitset(const std::basic_string<CharT, Traits, Alloc> &str, (1)
typename std::basic_string<CharT, Traits, Alloc>::size_type(2)
pos = 0,
(3)(since C++ 11)
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'));
template <class CharT>
explicit bitset(const CharT *str,
typename std::basic_string<CharT>::size_type(4)(since C++ 11)
n = std::basic_string<CharT>::npos,
CharT zero = CharT('0'),
CharT one = CharT('1'));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
32
(until C++11)
64
(since C++11) bits, for typical implementations of unsigned
long
(since C++11)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
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] in C++11
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';
}
Possible output:
See also
set (public member function)
reset (public member function)