enum in a namespace

Question

Is there a point of doing somthing like this:

namespace status{   enum status{     ok,     error   }; } 

and use it like that status::ok

Or should i do this:

enum status{   status_ok,   status_error }; 

and use it like this status_ok?

Update: With C++11 you now should do this:

enum class status {     ok,     error }; 

and use like this: status::ok

Answer 1

I personally don't like the second variation because the status_ part seems redundant to me. The former version avoids that problem, but having a type status::status looks strange too. Furthermore, a namespace is open to modification, so in case somebody did something like

namespace status {   void error( const char *msg ); } 

You would get a compiler error since the function error clashes with your enum value.

I prefer to use a third variation:

struct MouseButton {   enum Value {     Left, Middle, Right   }; }; 

This lets me write functions like

void handleMouseButton( MouseButton::Value b ) {   switch ( b ) {     case MouseButton::Left:   // ...     case MouseButton::Middle: // ...     case MouseButton::Right:  // ...   } }