std::bitset::bitset

(1) default constructor

The object is initialized with zeros.

(2) initialization from integer value

Initializes the object with the bit values of val:

(3) initialization from string or (4) C-string

Uses the sequence of zeros and/or ones in str to initialize the first n bit positions of the constructed bitset object.

Parameters

val

Integral value whose bits are copied to the bitset positions.
- If the value representation of val is greater than the bitset size, only the least significant bits of val are taken into consideration.
- If the value representation of val is less than the bitset size, the remaining bit positions are initialized to zero.

str

A basic_string whose contents are used to initialize the bitset:
The constructor parses the string reading at most n characters beginning at pos, interpreting the character values '0' and '1' as zero and one, respectively.
Note that the least significant bit is represented by the last character read (not the first); Thus, the first bit position is read from the right-most character, and the following bits use the characters preceding this, from right to left.
If this sequence is shorter than the bitset size, the remaining bit positions are initialized to zero.

A basic_string or C-string whose contents are used to initialize the bitset:
The constructor parses the string reading at most n characters (beginning at pos for (3)), interpreting the character values specified as arguments zero and one as zeros and ones, respectively.
Note that the least significant bit is represented by the last character read (not the first); Thus, the first bit position is read from the right-most character, and the following bits use the characters preceding this, from right to left.
If this sequence is shorter than the bitset size, the remaining bit positions are initialized to zero.

pos

First character in the basic_string to be read and interpreted.
If this is greater than the length of str, an out_of_range exception is thrown.

n

Number of characters to read. Any value greater than the bitset size (including npos) is equivalent to specifying exactly the bitset size.

zero, one

Character values to represent zero and one.

Example

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// constructing bitsets
#include <iostream>       // std::cout
#include <string>         // std::string
#include <bitset>         // std::bitset
int main ()
{
  std::bitset<16> foo;
  std::bitset<16> bar (0xfa2);
  std::bitset<16> baz (std::string("0101111001"));
  std::cout << "foo: " << foo << '\n';
  std::cout << "bar: " << bar << '\n';
  std::cout << "baz: " << baz << '\n';
  return 0;
}

foo: 0000000000000000
bar: 0000111110100010
baz: 0000000101111001

Data races

Exception safety

See also

bitset::set

Set bits (public member function)

bitset::reset

Reset bits (public member function)

bitset::operator[]

Access bit (public member function)

bitset operators

Bitset operators (function)