C / C++ / MFC

// a.h<br />
class b;<br />
class a : public A<br />
{<br />
public:<br />
    // Constructor, Destructor, and other members and functions. (Omitted)<br />
    //...<br />
    //<br />
    void SomeFunction();<br />
    b* m_pb;<br />
};<br />
<br />
// a.cpp<br />
#include "a.h"<br />
#include "b.h"<br />
void a::SomeFunction()<br />
{<br />
    MEMBERVARIABLEDATATYPE Member_Variable_of_b = m_pb->MemberVariable; // This would cause compiler error<br />
}<br />
<br />
// b.h<br />
class a;<br />
class b : public B<br />
{<br />
public:<br />
    // Constructor, Destructor, and other members and functions. (Omitted)<br />
    //...<br />
    //<br />
    a* m_pa;<br />
    MEMBERVARIABLEDATATYPE MemberVariable;<br />
    // MEMBERVARIABLEDATATYPE is well defined, for example, int, double, etc.<br />
};