How can I use a C++ unordered_set for a custom class?

Question

How can I store objects of a class in an unordered_set? My program needs to frequently check if an object exists in this unordered_set and if it does,

Answer 1

You need to implement a custom hash function (I'd suggest using the function in the Boost library) to do this. C++ allows you to save pointers to objects of a class using unordered_set. For most purposes, that should do the trick.