This could be useful for combinatorial tasks such as iterating over all the ways to draw 𝑘 items without replacement from a bag containing 𝑛 distinct items. Y

This could be useful for combinatorial tasks such as iterating over all the ways to draw 𝑘 items without replacement from a bag containing 𝑛 distinct items. You start out with 1<<𝑘 – 1 (which has its 𝑘 low-order bits set to 1) and keep going up to the next higher integer with the same popcount until bit 𝑛 is set to 1, at which point you stop.