How to have classes call each other's method?

[zenkiboy]

i have read the topic at http://www.cplusplus.com/forum/beginner/6075/
it is helpful. but i have a further question: how these two objects call each other's method? such as:

File: classA.h:

#ifndef CLASSA_H
#define CLASSA_H

class B;   // forward declaration

class A {
   B* pB;
   pB->B_method();
};

#endif  

File: calssB.h

#ifndef CLASSB_H
#define CLASSB_H

class A;   // forward declaration

class B {
   A* pA; 
   pA->A_method();
};

#endif  

it seems can not compile becasue pB->B_method() can not be known by class A according to "class B //forward declaration". how could i achieve this without include header file?

Thanks in advance.

[Bazzy]

You can define the function bodies in an external cpp file (you wouldn't call pA->A_method out of a B member function)

eg:

//ClassB.cpp
#include "ClassA.h"
#include "ClassB.h"

void B::member_function ()
{
   pA->A_method();
}

[zenkiboy]

Thanks for your solution, problem solved. definitely call pA->A_method must be in B's member function. sorry for my mistake before.
anyway, still curious if its possible just using forward declaration??

[z05DSL3A]

still curious if its possible just using forward declaration??

Simple answer, No.

You can not use any members of class A until you have a definition for class A. The declaration just says that there is a class A.