Circular reference

[vbourbeau]

Hi,

I don't know how to avoid circular reference. Classe B need a object of class C and C one of B?

#include B.h
Class A
{
}

#include C.h
Class B
{
}

include B.h
Class C
{
}

[dhayden]

Class B need a object of class C and C one of B?

They can't actually contain each other, but they can have pointers or references to each other.

To see why this is, consider how big C and B would have to be if they could contain each other. An instance of C would have to be at least as big as B, since it contains a B. But an instance of B would have to be at least as big as C since it contains a C. They would each have to be infinitely large to contain the other.

To deal with the circular reference, you do a forward declaration:

file B.h:

class C;  // forward declaration

class B {
    C *cp;
};

file C.h:

class B;  // forward declaration

class C {
    B *bp;
};

[vbourbeau]

I mean a instance of each other

[keskiverto]

Please show your current definitions of B and C.

[vbourbeau]

Ok with the forward declaration.

Thank

[keskiverto]

You want to create object of type C. It has one B object inside. That B has one C object inside. That C has one B object inside. That B has one C object inside. That C has one B object inside. ...

You can't have infinite recursion.

You have to rethink your design.