get the next greatest neighbor in bitset

next_ge_bitset.cpp

#include <iostream>
#include <bitset>

int next_ge(uint64_t S, int k) {
    uint64_t mask = ~((1ULL << k) - 1);
    uint64_t candidates = S & mask;
    return __builtin_ctzll(candidates);
}


int main(int argc, char const *argv[])
{
	std::cout << size_t(next_ge(((uint64_t)1 << 32) | (1 << 26), 23)) << "\n";
	return 0;
}