How to make a derived class access the private member data?

Question

I'm stuck with a c++ problem. I have a base class that has a self referential object pointer inside the private visibility region of the class. I have a constructor in the base class that initializes these two pointers. Now I have my derived class whose access specifier is private(I want to make the public member functions of my base class private). Now through the member functions of my derived class I want to create an object pointer which can point to the private data of the base class, that is ,those self referential object pointers. My code is:

class base{
private:
     base *ptr1;
     int data;
public:
     base(){}
     base(int d) { data=d }
};

class derived:private base{
public:
     void member()
};

void derived::member()
{
base *temp=new base(val); //val is some integer
temp->ptr1=NULL; //I can't make this happen. To do this I had to declare all the
                 //private members of the base class public. 
}

Answer 1

Derived class can not access the private members of it's base class. No type of inheritance allows access to private members.

However if you use friend declaration you can do that.