yes you're right I'm sorry,I just thought it was a general procedure to mix c with c++.
Anyway I'm using Visual Studio 2008 and the error I'm getting is :

fatal error C1083: Cannot open include file: 'A.h': No such file or directory

I have a .c file where is the main function and includes :

Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "A.h"         
#include "B.h"         
#include "C.h"    
#include "D.h"
the A.h has functions declarations and doesn't include anything.

the B.h and the C.h have also functions declarations and include the following:

Code:
#include "A.h"
#include "D.h"
#include "E.h"
#include <stdio.h>
#include <iostream>
#include <string.h>
#include <stdlib.h>

using namespace std;
the D.h has only a struct definition and includes

Code:
#include <stdio.h>
#include <iostream>
the E.h has a class definition and includes

Code:
#include <iostream>
#include <string.h>
#include <stdlib.h>
#include "A.h"
#include "D.h"
#include "F.h"

using namespace std;
the F.h has a class definition as well and includes:

Code:
#include <stdio.h>
#include <string>
#include <iostream>
#include <stdlib.h>
#include "A.h"
#include "D.h"
#include "E.h"

using namespace std;

and then are the .cpp files which have either functions or class functions depending on their header file.