How to access member of a class of one branch of hierarchy using pointer of class from another branch?

Question

              class A
              /     \
          class B1  class B2

All classes have only public members.

Class A is publicly inherited and contains virtual member functions and non-virtual member functions with default print(cout) statements, class B1 and class B2 has only non-virtual functions, with definition of the virtual functions from class A.

I want to know how to access all members of B2 using pointer of B1, which casting could be used.

For example:

B2 obj_b2;
B1* b1_ptr=&obj_b2;

// Using b1_ptr, access all members of obj_b2

If yes, then whether this can be extended further into more deep branches like:

              class A
              /     \
          class B1  class B2
            /   \     /   \
       class C1 ...  ...  ...

(Accessing members of class C1, etc. from second branch)

---

EDIT 1:

Maybe this will help; this is the example that I have written:

#include<iostream>
using namespace std;
class A{
public:
    virtual void v_f1(){
        cout<<"virtual A::v_f1()\n";
    }
    void f1(){
        cout<<"A::f1()\n";
    }
};
class B1 : public A{
public:
    virtual void v_f2(){
        cout<<"virtual B1::v_f2()\n";
    }
    void v_f1(){
        cout<<"A<-B1::v_f1()\n";
    }
    void f2(){
        cout<<"B1::f2()\n";
    }
};
class C1 : public B1{
public:
    void v_f2(){
        cout<<"B1<-C1::v_f2()\n";
    }
    void f3(){
        cout<<"C1::f3()\n";
    }
};
class D : public C1{
public:
    void f4(){
        cout<<"D::f4()\n";
    }
};
class B2 : public A{
public:
    void v_f(){
        cout<<"A<-B2::v_f()\n";
    }
    void f5(){
        cout<<"B2::f5()\n";
    }
};
class C2 : public B2{
public:
    void f6(){
        cout<<"C2::f6()\n";
    }
};
int main(){
    C2 c2_obj;
    C2* c2_obj_ref=&c2_obj;
    D* d_ptr = dynamic_cast<D*>(c2_obj_ref);

    // This statement gives segmentation fault,
    // if commented out, the code works fine.
    d_ptr->v_f();

    // These work fine
    d_ptr->f();
    dynamic_cast<C2*>(d_ptr)->f5();
    dynamic_cast<C2*>(d_ptr)->f6();
    return 0;
}

Answer 1

An object of type B1 does not have the members that B2 declares.

If you try to treat an object as a type that it is not, your program is ill-formed.

Answer 2

You basically can't.

B1 inherits from A, but know nothing from any other class the inherits from A. You can upcast a B1 object to A or down cast A to a B1 objet. If you do both you'll eitehr have a bad cast exception or a null ptr (see comments)

What you are doing here is upcasting a B2 to A then downcasting an A to a B1 (if it compiles what I'm not sure of) so you may loose some B2 informations from the upcast that you can recollect in you downcast.

If you want to do this, you should rather wonder if B1 and B2 are basically the same class and should differ in a different way. For instance is say A is Character, B1 is Soldier and B2 is Creature, you could just have class A and inherited class AInstance with a private parameter bool soldier and bool creature that you can then use for printing or algorithm purposes.

Hope that helps !