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

The basic advantage of using enum class over normal enums is that you may have same enum variables for 2 different enums and still can resolve them(which has been mentioned as type safe by OP)

For eg:

enum class Color1 { red, green, blue };    //this will compile
enum class Color2 { red, green, blue };

enum Color1 { red, green, blue };    //this will not compile 
enum Color2 { red, green, blue };

As for the basic enums, compiler will not be able to distinguish whether red is refering to the type Color1 or Color2 as in hte below statement.

enum Color1 { red, green, blue };   
enum Color2 { red, green, blue };
int x = red;    //Compile time error(which red are you refering to??)