Thread: Class vs. Namespace as Singleton

I was looking across some code and I found an unusual technique to implement public singletons. I have never seen this code style before in any code.

Here's an example of generic singleton code:

Code:

class Test {
private:
	Test() {}
	Test(const Test&);
	Test& operator=(const Test&);
public:
	char mem[0xFFF];
	static Test& Instance() {
		static Test instance;
		return instance;
	}
	void DoStuff(int i) {
		mem[i] = i*2;
	}
};

and to access:

Code:

Test::Instance().DoStuff(5);
Test::Instance().mem[2] = 10;

And here's an example that does the same thing, just with namespaces.

Code:

namespace Test {
	char mem[0xFFF];
	void DoStuff(int i) {
		mem[i] = i*2;
	}
}

Code:

Test::DoStuff(5);
Test::mem[2] = 10;

I was wondering, what are the benefits and drawbacks of either technique? Why would someone choose to implement a singleton class if they want all attributes public? Is there a performance gain by using one of the techniques? And, what are your thoughts on using namespaces like this?

Thanks,
eros.