c++11 - define enum class with same name compared to enum

Question

Why this compiles in c++11:

struct foo
{
  enum class Resolution { None=10, Nominal=20 };
  enum class Scale { None, Nominal };
};

while this doesn't:

struct foo
{
  enum Resolution { None=10, Nominal=20 };
  enum Scale { None, Nominal };
};

?

Answer 1

在 C++11 枚举值没有作用域之前，这意味着 2 个枚举中的值不能相同。使用时不再是这种情况enum class。