Help with multiple classes

[Xds]

Hi all, This is my first post; I'm new to C++ so go easy on me. I have two classes; and their functions include code that refer to the other: i.e: Class X has code that uses a variable/function from Class Y and vice-versa. The classes are completely different, so it would not help to derive one off the other. In Header.h:

------------------------------------------------------------
class X {
public:
int myint;
void doit(void);
};

void X::doit(void) {
printf("CY.myint = %i", CY.myint); // Print Class Y's myint
}

class Y {
public:
int myint;
void doit(void);
};

void Y::doit(void) {
printf("CX.myint = %i", CX.myint); // Print Class X's myint
}

In Main.CPP:

------------------------------------------------------------
#include "stdio.h"
#include "Header.h"

int main(void) {

class X CX;
class Y CY;

CX.myint = 100;
CY.myint = 200;
CX.doit();
CY.doit();

return 1;

}

How can I get these classes to work together? I can't put an 'extern class Y' before the 'class X' declaration, so how can I let the compiler know that the other class exists and will be declared? Thanks! Mike

[Rickard Andersson20]

Xds wrote: int main(void) { class X CX; class Y CY; CX.myint = 100; CY.myint = 200; CX.doit(); CY.doit(); return 1; } I'm not sure about this but isn't it "wrong" to write 'class X CX'? Isn't 'X CX' the right way!? I can be wrong!!!!!! ------------------------------------ Rickard Andersson, Suza Computing ICQ#: 50302279 I'm from the winter country SWEDEN! ------------------------------------

[Xds]

Pretty sure it works either way, but in any case, that's not the problem. Thanks! Mike

[Roger Allen]

You need to use a forward declaration of the class.

class Y ; // forward class declaration

class X
{
void DoIt(Y& y) ; // pass in a reference to a Y object
} ;

class Y
{
} ;

You also cannot print out the content of CY in CX unless you pass a reference / pointer / copy of the object you want to print in as a parameter. The CX in main does not know anything about the CY:

#include "stdio.h"
#include "Header.h"
int main(void)
{
X CX;
Y CY;
CX.myint = 100;
CY.myint = 200;
CX.doit(CY); // see class declaration above
CY.doit();
return 1;
}

Roger Allen Sonork 100.10016 If I'm not breathing, I'm either dead or holding my breath. A fool jabbers, while a wise man listens. But is he so wise to listen to the fool?

[Le centriste]

That code wont't compile because in your doit methods you reference hard-coded instances. Michel If I am wrong or said something stupid, I apologize in advance ;)