<xstd/bits/bit_algorithm/bit_count.hpp>

bit_count

As ranges::count in [alg.count], with:

• Constraints: R is a sequence of ours, a window included.
• Returns: The number of positions of r holding value, as ranges::range_difference_t<const R>, signed as ranges::count's result is: the ones popcounted, and the zeros as ranges::size(r) less the ones.
• Complexity: O(N/D) popcounts. The padding of the last block is never counted.