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std::bitset<N>:: flip

From cppreference.net
C++
Utilities library
std::bitset
bitset & flip ( ) ;
(1) (noexcept since C++11)
(constexpr since C++23)
bitset & flip ( std:: size_t pos ) ;
(2) (constexpr since C++23)

Flips bits, i.e. changes true values to false and false values to true . Equivalent to a logical NOT operation on part or all of the bitset.

1) Flips all bits (like operator~ , but in-place).
2) Flips the bit at the position pos .

Contents

Parameters

pos - the position of the bit to flip

Return value

* this

Exceptions

2) Throws std::out_of_range if pos does not correspond to a valid bit position.

Example

Run this code 
#include <bitset>
#include <iostream>
int main()
{
    std::bitset<4> flops;
    std::cout << flops << '\n'
              << flops.flip(0) << '\n'
              << flops.flip(2) << '\n'
              << flops.flip() << '\n';
}

Output: 

0000
0001
0101
1010

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 2250 C++98 the behavior was undefined if pos does
not correspond to a valid bit position 		always throws an
exception in this case

See also

sets bits to true or given value
(public member function)
sets bits to false
(public member function)
performs binary AND, OR, XOR and NOT
(public member function)
flips all the bits
(public member function of std::vector<bool,Allocator> )