operator<<,>>(std::bitset)
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Defined in header
<bitset>
template< class CharT, class Traits, std::size_t N >
(1)
std::basic_ostream <CharT, Traits>&
template< class CharT, class Traits, std::size_t N >
(2)
std::basic_istream <CharT, Traits>&
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.
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
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').
[edit] Parameters
os
-
the character stream to write to
is
-
the character stream to read from
x
-
the bitset to be read or written
[edit] Return value
1) os
2) is
[edit] 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
[edit] 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 comparesit 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
|