brianj@witsend.cs.umd.edu (Brian Johnson) (09/06/90)
What do I need to do in order to let two classes "talk" to each other.
It took me awhile to figure out that this was my problem. Is there
some sort of forward declaration for classes (class structs)
referenced in this way.
Here are four sample files.
Example Code:
#define _H_Class1 /* Include this file only once */
#include "Class3.h"
struct Class1 : indirect {
Class3 *three;
void doit(void);
};
---------------------
#include "Class1.h"
#include <Stdio.h>
void Class1::doit(void) {
printf("I'm Class One.");
}
---------------------
#define _H_Class3 /* Include this file only once */
#include "Class1.h"
struct Class3 : indirect {
Class1 *one;
void doit(void);
};
---------------------
#include "Class1.h"
#include <Stdio.h>
void Class3::doit(void) {
printf("I'm Class Three.");
}
Thanks,
--
Brian Johnson Computer Science Department
brianj@cs.umd.edu University of Maryland
(301) 405-2725 College Park, Md 20742 dbw@cup.portal.com (Dale B Walker) (09/08/90)
You Write: >What do I need to do in order to let two classes "talk" to each other. >It took me awhile to figure out that this was my problem. Is there >some sort of forward declaration for classes (class structs) >referenced in this way. In your examples you have two .h files that include each other. I encountered the same problem. My solution was to have only one of the files include the other - and in the case of the second file, use the superclass of the desired class and cast it as necessary in the c code defining the methods. Dale Example: /* Class1.h */ #define _H_Class1 #include <CObject.h> struct Class1 : indirect { CObject *three; void doit (void); }; ------------------------------- /* Class3.h */ #define _H_Class3 #include <CObject.h> #include "Class1.h" struct Class3 : CObject { Class1 *one; void doit (void); }; -------------------------------- /* Class1.c */ #include "Class1.h" #include "Class3.h" void Class1::doit() { ((Class3 *) three)->doit(); }