C++ enum redefenition and C++0x

If I want to exclude problems with enums and type redefinition in C++ I can use the code:

struct VertexType
{
    enum
    {开发者_JAVA百科
        Vector2 = 1,
        Vertor3 = 2,
        Vector4 = 3,
    };
};

struct Vector2 { ... };
struct Vector3 { ... };
struct Vector3 { ... };

Is there a way to remove the wrapper above enum. I looked at C++0x but didn't find addiditional inforamtion about solving this problem.

Since you are talking about C++0x, just use the new enum class syntax:

enum class VertexType {
   Vector1 = 1,
   Vector2 = 2,
   Vector4 = 3
};

The enumerator values will only be accessible through the VertexType type as in VertexType::Vector1.

Some quotes from the standard:

§7.2/2 [...] The enum-keys enum class and enum struct are semantically equivalent; an enumeration type declared with one of these is a scoped enumeration, and its enumerators are scoped enumerators. [...]

§7.2/10 [...] Each scoped enumerator is declared in the scope of the enumeration.[...]

// example in §7.2/10
enum class altitude { high=’h’, low=’l’ };
void h() {
  altitude a;        // OK
  a = high;          // error: high not in scope
  a = altitude::low; // OK
}

How about namespace?

namespace VertexType
{
    enum V
    {
        Vector2 = 1,
        Vertor3 = 2,
        Vector4 = 3,
    };
}

struct Vector2 { ... };
struct Vector3 { ... };
struct Vector4 { ... };

It appears vector3 is already being used. You can do what your trying to do, however, vector3 cannot be used.

enum //VertexType
{
    Vector2 = 1,
    //Vector3 = 2,
    Vector4 = 3,
};

struct Vector2 { ... };
//struct Vector3 {  };
struct Vector3 { ... };

This works for me, no errors at all.

This is a link i found. http://www.kixor.net/dev/vector3/