Simple problem with classes

Hi everyone,


Well, I have 3 classes in 3 files:


Main class father, at father.h:

Code:

---

#if ! defined ( Father_C )
#define Father_C

#include <stdio.h>

#include "son.h"
#include "daughter.h"


class Father
{
private:
        son *sons;
        daughter *daughters;

public:
        Father(){
                son jack;
               
        };
        ~Father();

};

#endif

---

at son.h:

Code:

---

#if ! defined (Son_C )
#define Son_C

#include <stdio.h>

#include "daughter.h"


class son
{
private:
        daughter *sisters;

public:
        son(){
                daughter jamie;
               
        };
        ~son();

};

#endif

---

at daughter.h:

Code:

---

#if ! defined (Daughter_C )
#define Daughter_C

#include <stdio.h>

#include "son.h"


class daughter
{
private:
      son *brothers;

public:
        daughter(){
                son jack;
               
        };
        ~daughter();

};

#endif

---

But it doesnt work, I am unable to reference 2 classes between themselves, as I did in the example with son and daughter. I would like to references those clases between them and with the father, as i did at the example.

I know it is not much difficult, I will appreciate a lot any help or references.


Thank you very much

David

What you are trying to do is a circular arrangement of classes, where class A contains class B, which in turn contains class A. Since the compiler needs to know the size and content of A to know the size and content of B, you'll end up with an infinite loop of unknown sizes.

You can use a reference or a pointer, but not include the class itself inside another class.

--
Mats

You have to use forward declarations instead of including the other headers. To declare a pointer (or a reference) the full type doesn't have to be known, the compiler simply needs to be assured that a class by this name exists.

Also see the comment about the constructor:

Code:

---

#if ! defined ( Father_C )
#define Father_C

//#include <stdio.h>  //not used

//#include "son.h"    //don't have to be included
//#include "daughter.h" //and cannot be if you have circular dependencies

//tell compiler that classes called son and daughter exist
class son;
class daughter;

class Father
{
private:
        son *sons;
        daughter *daughters;

public:
        Father(){
                //son jack;
/*
This doesn't do anything - it creates a local son object that only exists in the constructor
If you really need to do something like that, the full definition of Son must be available:
you have to provide the implementation in the separate cpp file that can include "son.h"
*/
               
        };
        ~Father();

};

#endif

---

Thank you !!!! I see it!