CCAN has a bitset implementation you can use: http://ccan.ozlabs.org/info/jbitset.html But if you do end up implementing it yourself (for instance if you don’t like the dependencies on that package), you should use an array of ints and use the native size of the computer architecture: #define WORD_BITS (8 * sizeof(unsigned int)) unsigned int * bitarray … Read more
For the specific problem you mentioned: when you called bits2.set(1000001), you set the one millionth and first bit to true. Then when you intersected with bits1, which had the one million, 111 thousand, and 111st bit set, they had no bits in common. I think what you meant to do was bits2.set(0); // set the … Read more
In “Effective STL,” Item 18, Scott Meyers recommended: “Avoid using vector< bool >.”: As an STL container, there are really only two things wrong with vector< bool >. First, it’s not an STL container. Second, it doesn’t hold bools. Other than that, there’s not much to object to.
The following code creates a bit set from a long value and vice versa: public class Bits { public static BitSet convert(long value) { BitSet bits = new BitSet(); int index = 0; while (value != 0L) { if (value % 2L != 0) { bits.set(index); } ++index; value = value >>> 1; } return … Read more
As selected answer says you can use findAndModify to generate sequential IDs. But I strongly disagree with opinion that you should not do that. It all depends on your business needs. Having 12-byte ID may be very resource consuming and cause significant scalability issues in future. I have detailed answer here.
Boost has a dynamic_bitset you can use. Alternatively, you can use a vector<bool>, which (unfortunately) is specialized to act as a bitset. This causes a lot of confusion, and in general is considered a bad idea. But that’s how it works, so if that’s what you need, you might as well use it, I suppose.