including headers inside headers

Hi all,

I have a header file "realTreeNode.h" and starts like this;

Code:

---

#ifndef REALTREENODE_H
#define REALTREENODE_H

#include "keyedItem.h"

#include
using namespace std;

typedef KeyedItem TreeItemType;

const int MAX_DIFF_PAGE_NUMBERS = 50;

typedef void (*FunctionType)(TreeItemType& anItem, TreeItemType pageNumbers[MAX_DIFF_PAGE_NUMBERS]);

class TreeNode // a node in the tree
{
....
};

---

In addition to this I have another header file "realBST.h" and starts like this;

Code:

---

#ifndef REALBST_H
#define REALBST_H

#include "realTreeException.h"
#include "realTreeNode.h"

typedef void (*FunctionType)(TreeItemType& anItem, TreeItemType pageNumbers[MAX_DIFF_PAGE_NUMBERS]);

class BinarySearchTree
{
...
};

---

The thing I want to do here is;

Creating a private BinarySearchTree object ( variable / property ) in TreeNode class.

However, when I add #include "realBST.h"in order to create a private BinarySearchTree member for TreeNode to "realTreeNode.h" file, it gives many irrelavent errors.

How could I solve this problem, any suggestions, any opinions would be helpful.

Best wishes,

Ok, if I am understanding you right you have a header file named realtreenode.h and another header named RealBST.h and you want to include realBST.h in in realtreenode.h and I am noticing that realBST.h already includes realtreenode. I won't go into infinite includes because I see you have the inclusion guards, but your problem is still realated.

The short answer is: two objects cannot mutually contain each other.

In other words if you have two classes Foo and Bar:

Code:

---

class Bar;// forward declaration

class Foo
{
        Bar mBar; // error - object not defined - we only have a declaration
        Bar* mptBar; // ok - this is the work around - you have to use pointers
};

class Bar

{
        Foo mFoo; // ok
};

---

If you need more explanation let me know.

Hi Darryl,

I got what you mean and it is a brilliant idea.

However, I cannot add the #include "realBST.h" into "realTreeNode.h" and therefore, I cannot even create a pointer to BinarySearchTree class. Since, realTreeNode header file do not know the BinarySearchTree class unless I add "realBST.h" as you know friend.

What could I do?

If you wish I can send the code to you.

Thanks,

I got it now, it works.

First declaration worked. I didn't include the header file, just declaration and a pointer did everything working well.

Thank you Darryl.

> using namespace std;
Don't put namespaces inside header files.
People including your header file might not want the namespace being polluted in this way.

Quote:

---

Originally Posted by Salem

> using namespace std;
Don't put namespaces inside header files.
People including your header file might not want the namespace being polluted in this way.

---

Agreed.