About C++ HashSet and unordered_set

[lucky6969b]

I am creating a container of std::set, but I need to search it in logarithmic time or constant time.
Sets don't provide such capabilities, so I look into hash sets,
I discover the C++ standard library provides something called unordered_set
But it needs to provide some comparator or override for the contained objects.
As before, I've a class which already implemented the

bool operator < (const AABB& other) const;

But this isn't enough, I still get some errors like these.

Error 1 error C2338: The C++ Standard doesn't provide a hash for this type. c:\program files (x86)\microsoft visual studio 12.0\vc\include\xstddef 328 1 Perfectsim

What other stuff do I need in order to compile for the unordered_set? I can't find good examples on the net.
Thanks
Jack

[lucky6969b]

Hello, I think I should have added a hashing function,
But how do I define a good hashing function for my need?
How do I design one to make the access time good?
Thanks
Jack

struct AABBHasher {
	size_t operator()(const AABB& aabb) const {
		return 0;
	}

	size_t operator()(const boost::shared_ptr<AABB>& aabb) const {
		return 0;
	}

};

The elements I need to look up are just x and z coordinates, probably add y later.

[2kaud]

Have a look at

http://www.azillionmonkeys.com/qed/hash.html
http://stackoverflow.com/questions/1...ated-data-type
http://stackoverflow.com/questions/1...-unordered-set

Also a search of MSDN comes up with many more articles that could be of interest
https://social.msdn.microsoft.com/Se...mark=true&ac=5