Bi-directional link between two class

[Robert]

Hi all,

I encounter a problem: I want to define two class, A has a point to B
and B also has a point to A. Something like a bi-directional link list.
But It has compile error.

//---code-------
class A
{
...
B* b;
}

class B
{
...
A* a;
}
//--------------
The error message is B is a unknown type.

Best regards,
Robert

 

[Matthias Kaeppler]

The error message is B is a unknown type.

That's because at the point of declaration of A::b, class B is unkown.
You have to forward-declare it:

//---code-------
class B;

class A
{
...
B* b;
};

class B
{
...
A* a;
};
//--------------