std::size_t count() const; | (until C++11) | |
std::size_t count() const noexcept; | (since C++11) (until C++23) | |
constexpr std::size_t count() const noexcept; | (since C++23) |
Returns the number of bits that are set to true.
(none).
number of bits that are set to true.
#include <iostream>
#include <bitset>
int main()
{
std::bitset<8> b("00010010");
std::cout << "initial value: " << b << '\n';
// find the first unset bit
std::size_t idx = 0;
while (idx < b.size() && b.test(idx)) ++idx;
// continue setting bits until half the bitset is filled
while (idx < b.size() && b.count() < b.size()/2) {
b.set(idx);
std::cout << "setting bit " << idx << ": " << b << '\n';
while (idx < b.size() && b.test(idx)) ++idx;
}
}Output:
initial value: 00010010 setting bit 0: 00010011 setting bit 2: 00010111
| returns the number of bits that the bitset holds (public member function) |
|
|
(C++20) | counts the number of 1 bits in an unsigned integer (function template) |
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