Do we really need “enum class” in C++11?

Question

When we have,

struct E { enum E_ { HELLO }; }; // \'E\' is inheritable

then why do we need,

enum class E { HELLO };  // \'E         


        

Answer 1

In the first case, the type of HELLO is not E, whereas in the second case, the type of HELLO is E.

For a good demonstration of why this is important, see Howard Hinnant's answer to "“enum class” emulation or solid alternative for MSVC 10.0."

enum class and enum struct are "semantically equivalent" (i.e., the same), per C++0x FDIS §7.2/2.