why it needs a copy ctor? why make copy constructor "protected"

I had a interview before?

my answer was just the same as yours. I passed.

it's something like the one below: (something wrong????)

class Singleton {
public:
static Singleton* Instance();
static proof(void);
protected:
Singleton();
private:
static Singleton* _singleton;
};

所有跟帖： 

• the interviewer said -吳用先生- ♂ (186 bytes) () 03/05/2009 postreply 12:31:48

• ok. -戲雨飛鷹- ♀ (0 bytes) () 03/05/2009 postreply 12:40:14