why can enum class values of type int not be used as int

Question

I wanted to change an old-style enum to enum class : int because of its own scope.

But the compiler complains about using the values in integer

Answer 1

Type safety is the main reason to use the new scoped enums (perhaps the name is a bit misleading). If you merely want an enum that is scoped and can implicitly convert to integers you can wrap it in a struct or namespace:

struct MsgSender {
   enum Values {
      A = 1,
      B = 2,
      C = 3
   };
};

Downside is that the type is now MsgSender::Values, but the values are MsgSender::A etc.

For a scoped enum you have to static_cast to the std::underlying_type to get the integer.