C++ unordered_map using a custom class type as the key

Question

I am trying to use a custom class as key for an unordered_map, like the following:

#include 
#include 
#include         


        

Answer 1

For enum type, I think this is a suitable way, and the difference between class is how to calculate hash value.

template 
struct EnumTypeHash {
  std::size_t operator()(const T& type) const {
    return static_cast(type);
  }
};

enum MyEnum {};
class MyValue {};

std::unordered_map> map_;