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

 

C++

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Symbols index

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Utilities library

Language support Type support (basic types, RTTI) Library feature-test macros (C++20) Dynamic memory management Program utilities Coroutine support (C++20) Variadic functions is_constant_evaluated (C++20) is_within_lifetime (C++26) initializer_list (C++11) source_location (C++20) Three-way comparison (C++20) three_way_comparablethree_way_comparable_with (C++20)(C++20) strong_ordering (C++20) weak_ordering (C++20) partial_ordering (C++20) common_comparison_category (C++20) compare_three_way_result (C++20) compare_three_way (C++20) strong_order (C++20) weak_order (C++20) partial_order (C++20) compare_strong_order_fallback (C++20) compare_weak_order_fallback (C++20) compare_partial_order_fallback (C++20)    is_eqis_neqis_ltis_lteqis_gtis_gteq (C++20)(C++20)(C++20)(C++20)(C++20)(C++20)

General utilities Date and time Function objects Formatting library (C++20) bitset hash (C++11) Relational operators (deprecated in C++20) rel_ops::operator!=rel_ops::operator> rel_ops::operator<=rel_ops::operator>= Integer comparison functions cmp_equalcmp_lesscmp_less_than (C++20)(C++20)(C++20)    cmp_not_equalcmp_greatercmp_greater_than (C++20)(C++20)(C++20) in_range (C++20) Swap and type operations swap ranges::swap (C++20) exchange (C++14) declval (C++11) to_underlying (C++23) forward (C++11) forward_like (C++23) move (C++11) move_if_noexcept (C++11) as_const (C++17) Common vocabulary types pair tuple (C++11) optional (C++17) any (C++17) variant (C++17) tuple_size (C++11) tuple_element (C++11) apply (C++17) make_from_tuple (C++17) expected (C++23) Elementary string conversions to_chars (C++17) from_chars (C++17) chars_format (C++17)

 

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)