Question

What I am trying to do is create a base class, for which anything derived from it will automatically be registered with another class, eg:

class System;
class Object
{
public:
    Object()
    {
        System sys;
        sys.AddObject(this);
    }
    virtual ~Object()
    {
        System sys;
        sys.RemoveObject(this);
    }
};
class System
{
public:
    // Some other processing function which operates on all things derived
    // from Object at one time.
    void ProcessAllObjectsInExistence();

    void AddObject(Object *o)
    {
        list.push_back(o);
    }
    void RemoveObject(Object *o)
    {
        std::vector<Object *>::iterator i = find(list.begin(), list.end(), o);
        if (*i != list.end()) list.erase(i);
    }
private:
    static std::vector<Object *> list;
};

Is this legal and defined? The reason why I am asking is because I am getting some funny errors after reading and writing to the data members of Object (not shown here) from inside ProcessAllObjectsInExistence().

i.e. for a single Object before I call System.ProcessAllObjectsInExistence() the members are 0 and 100, and then the first line inside ProcessAllObjectsInExistence() is a debugging line which prints the members and displays 0 and 0. painful ><

Answer 1

It is perfectly valid to refer to this inside a Base class.
However, calling virtual methods(if you have any) inside the Base class won’t actually work the way you think it should.