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

Because, as said in other answers, class enum are not implicitly convertible to int/bool, it also helps to avoid buggy code like:

enum MyEnum {
  Value1,
  Value2,
};
...
if (var == Value1 || Value2) // Should be "var == Value2" no error/warning