Including Files

I'm trying to do something like this:

MainClass.h:

Code:

---

#ifndef __MAIN_CLASS_H
#define __MAIN_CLASS_H

#include "SecondaryClass.h"

class MainClass
{
        private:
                SecondaryClass *secondaryClass;
               
        public:
                MainClass();
                ~MainClass();
       
};

#endif

---

SecondaryClass.h:

Code:

---

#ifndef __SECONDARY_CLASS_H
#define __SECONDARY_CLASS_H

#include "MainClass.h"

class SecondaryClass
{
        private:
                MainClass *m_mainClass;
               
        public:
                SecondaryClass( MainClass* );               
                ~SecondaryClass();
};

#endif

---

And I get the following errors:

Quote:

---

In file included from MainClass.h:4,
from main.cpp:2:
SecondaryClass.h:9: error: ISO C++ forbids declaration of `MainClass' with no type
SecondaryClass.h:9: error: expected `;' before '*' token

make.exe: *** [main.o] Error 1

---

I'm sure this is because I am including a file that includes the file I'm currently in.

The point of this being that MainClass has a member variable of Secondary class, which also has a reference to the MainClass that instantiated it.

Any ideas on how to accomplish this?

I think because never reashes to the end of the class...
See, is like this:
1) start header A.
2) header A calls header B.
3) start header B.
4) header B calls header A.
5) start header A.
6) header A calls header B, again!!!! why I didn't end the step 1 header A ?
...

Never reashes to the end of the class, because you are like inner loop or something the header over and over and over

I don't think that would be the case due to the #ifndef #endif block around the code. The class is only defined once -- the second time, the code in the block should be ignored. Correct?

Correct! But see this:
Even is "in used" the header, it never reashes the end of the header MainClass.

I have no idea what you are talking about.

And I don't why are you using this kinda code :p

Is there something wrong with it?

I think what Kal-El means, is this:

C++ Code:

#ifndef __MAIN_CLASS_H
#define __MAIN_CLASS_H
 
// #include "SecondaryClass.h"
 
class MainClass
{
    private:
        SecondaryClass *secondaryClass;
        
    public:
        MainClass();
        ~MainClass();
    
};
 
#include "SecondaryClass.h" // Put it here, because the preprocessor will know what MainClass is now..
 
#endif

Although, I'm not sure if that is correct.. I'll test it soon and get back to you.

chem

Chemical, I do not believe I can do that, because MainClass needs to have the definition of SecondaryClass.

I've never tried something like this.. as I've never had the need to. What you might need, is a friend class to both of your current classes, which handles the information between the two.

I'll stuff around with your code for a bit and get back to you.

chem

Actually.. silly me.

Just forward declare the classes:

MainClass.h

C++ Code:

#ifndef __MAIN_CLASS_H
#define __MAIN_CLASS_H
 
#include "SecondaryClass.h"
 
class SecondaryClass; // <------
 
class MainClass
{
    private:
        SecondaryClass *secondaryClass;
        
    public:
        MainClass();
        ~MainClass();
    
};
 
#endif

SecondaryClass.h

C++ Code:

#ifndef __SECONDARY_CLASS_H
#define __SECONDARY_CLASS_H
 
#include "MainClass.h"
 
class MainClass; // <--------
 
class SecondaryClass
{
    private:
        MainClass *m_mainClass;
        
    public:
        SecondaryClass( MainClass* );       
        ~SecondaryClass();
};
 
#endif

chem