Why is enum class preferred over plain enum?

Question

I heard a few people recommending to use enum classes in C++ because of their type safety.

But what does that really mean?

Answer 1

One thing that hasn't been explicitly mentioned - the scope feature gives you an option to have the same name for an enum and class method. For instance:

class Test
{
public:
   // these call ProcessCommand() internally
   void TakeSnapshot();
   void RestoreSnapshot();
private:
   enum class Command // wouldn't be possible without 'class'
   {
        TakeSnapshot,
        RestoreSnapshot
   };
   void ProcessCommand(Command cmd); // signal the other thread or whatever
};