std::bitset::set

From cppreference.com
< cpplrm; | utilitylrm; | bitset
bitset<N>& set();
(1)
bitset<N>& set( size_t pos, bool value = true );
(2)

Sets all bits to true or to specified value.

1) Sets all bits to true.
2) Sets the bit at position pos to the value value.

Parameters

pos - the position of the bit to set (least significant to most significant)
value - the value to set the bit to

Return value

*this

Exceptions

1)
(none) (until C++11)
noexcept specification:
noexcept
(since C++11)
2) Throws std::out_of_range if pos does not correspond to a valid position within the bitset.

Example

#include <iostream>
#include <bitset>

int main()
{
    std::bitset<8> b;
    for (size_t i = 1; i < b.size(); i += 2) {
        b.set(i);
    }
    std::cout << b << '\n';
}

Output:

10101010

See also

sets bits to false
(public member function)
toggles the values of bits
(public member function)