I'm studying patterns, I have a question about the Singleton pattern, should it look something like this?

Question

C++ / C#

Now I’m busy with patterns, the next step is Singleton, I correctly understood that it should look something like this (in all sources they are written differently), tell me the most clear and accurate implementation.
Looks like this for me:

#include <iostream>

class Singleton {
public:
    static Singleton* Instance() {
        if (instance == 0) {
            instance = new Singleton;
        }
        return instance;
    }
protected:
    Singleton();
private:
    static Singleton* instance;
};

Answer 1

Something like this, but it's better to forbid copying

Singleton(Singleton const&) = delete;
Singleton& operator= (Singleton const&) = delete;

Answer 2

I would recommend the Myers version . At least because of the thread-safe initialization.