Okay, I understand forward declarations, but I need to call members / fields on BOTH ends in this case, so I can't use that. I tried to overwrite the declaration inside the .cpp file (by including the actual header of the class I need to use) but the pointer I defined in the header via forward declaration was broken when I tried to use it.
How can I get around this? Do you need code ?
You need to keep in mind that forming a pointer to a class only requires a declaration of that class, while accessing that class's members requires its definition. So to solve circular dependencies, you can do this:
A.hpp
class B;
class A
{
public:
int foo(B *b);
int bar();
};
B.hpp
class A;
class B
{
A *m_a;
public:
int foo();
explicit B(A *a) : m_a(a) {}
};
A.cpp
#include "A.hpp"
#include "B.hpp"
int A::foo(B *b)
{
return 2 * b->foo();
}
int A::bar()
{
return 42;
}
B.cpp
#include "A.hpp"
#include "B.hpp"
int B::foo()
{
return m_a->bar();
}
If you're the only one that will have access to the inside of the code (like when you're doing a project for yourself, alone, or distributing a closed .lib/.dll), and you're sure you need your classes to include themselves in a circular way, you could always use an abstract base class.
class base{};
class A: public base{
base *bMember;
};
class B: public base{
base *aMember;
};
That's a bit of a bad practice, but if you need a straight solution, it should be sufficient. A better way would be to fix the dependencies or use separate base classes.
