C++ pointer by reference problem.

[dragonKlavier]

Hello.

I have problems with pointers by reference topic. This is the isue:

I have in a qt program:

- One class "A" with a class "B" and "C" instanced inside.
- A class D. This constains a set of Strings. And it is declared as a data member in "A" ,"B" and "C".


The problem is that I have to modify the "D" values (I have an instance of D class in A ,B and C) in any of the three classes and I need to manage a same value.

So, I think:

Class A.
{
   B * m_b;
   C * m_c;
   D * m_d;
 
 
   A()
   {
   m_b= new B(&m_d);
   m_c= new C(&m_d);
   }
}
 
Class B.
{
  D* m_d;
 
  B(D* &d)
  {
  m_d=d
  }
}
 
 
 
Class C.
{
  D* m_d;
 
  C(D* &d)
  {
  m_d=d
  }
}

Class A.
{
   B * m_b;
   C * m_c;
   D * m_d;

   
   A()
   {
   m_b= new B(&m_d);
   m_c= new C(&m_d);
   }
}

Class B.
{
  D* m_d;
  
  B(D* &d)
  {
  m_d=d
  }
}



Class C.
{
  D* m_d;
  
  C(D* &d)
  {
  m_d=d
  }
}

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My problem is that before y create m_d in B, I cant see the address in m_d of C.

Plese...I need your help

Thanks a lot!

[anda_skoa]

If you only need to modify the values of the D instance, you can simply pass pointers to the D instance.
You only need a reference to the pointer if you need to change the pointer itself.

Just create the D instance before you create the B and C instance.

Cheers,
_

[dragonKlavier]

thanks to all of you!!

My problem were....I passed the pointer by reference before I declared it.. lol..XD!

The only unusual issue is that the compiler give not me an error.

Thaks!!