operator<<,>>(std::bitset)

 

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std::bitset

Member types
bitset::reference
Member functions
bitset::bitset
bitset::operator==bitset::operator!= (until C++20)
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)

 

Defined in header <bitset>
template< class CharT, class Traits, std::size_t N > std::basic_ostream<CharT, Traits>&     operator<<( std::basic_ostream<CharT, Traits>& os, const std::bitset<N>& x );	(1)
template< class CharT, class Traits, std::size_t N > std::basic_istream<CharT, Traits>&     operator>>( std::basic_istream<CharT, Traits>& is, std::bitset<N>& x );	(2)

Inserts or extracts a bitset from a character stream.

1) Writes the bitset x to the character stream os as if by first converting it to a std::basic_string<CharT, Traits> using to_string(), and then writing it into os using the operator<< (which is a FormattedOutputFunction for strings).
The characters to use for ones and zeroes are obtained from the currently-imbued locale by calling std::use_facet<std::ctype<CharT>>(os.getloc()).widen() with '1' and '0' as arguments.

2) Behaves as a FormattedInputFunction. After constructing and checking the sentry object, which may skip leading whitespace, extracts up to N characters from is and stores the characters in the bitset x.
Characters are extracted until either

• N characters have been read,
• end-of-file occurs in is, or
• the next character is neither is.widen('0') nor is.widen('1').

If N > 0 and no characters are extracted, is.setstate(ios_base::failbit) is called.

Parameters

os	-	the character stream to write to
is	-	the character stream to read from
x	-	the bitset to be read or written

Return value

1) os

2) is

Example

Run this code

#include <bitset>
#include <iostream>
#include <sstream>
 
int main()
{
    std::string bit_string = "001101";
    std::istringstream bit_stream(bit_string);
 
    std::bitset<3> b1;
    bit_stream >> b1; // reads "001", stream still holds "101"
    std::cout << b1 << '\n';
 
    std::bitset<8> b2;
    bit_stream >> b2; // reads "101", populates the 8-bit set as "00000101"
    std::cout << b2 << '\n';
}

Output:

001
00000101

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 303	C++98	single-byte characters were extracted from is, but CharT can have multiple bytes	extracts CharT and compares it with widened '0' and '1'
LWG 396	C++98	the content written by operator<< was locale-independent	writes widened '0's and '1's
LWG 3199	C++98	extracting a std::bitset<0> always sets failbit	such extraction never sets failbit

See also

operator<<=operator>>=operator<<operator>>

performs binary shift left and shift right (public member function)