error C2079: 'CLASSA::objectb' uses undefined class 'CLASSB'

confuse about how that works, here, i would try to make it very clear,

Code:

---

// file 2
CLASS B
{
...
};

// file 1

CLASSB b; // forward declaration

CLASS A
{
...
B b; // error
};

but...,
// file 1
CLASS A
{
...
B * b; // okey
};

so what i did is,

// file 1
CLASS B
{
...
};

CLASS A
{
...
B b; // now okey
};

---

why?? what was wrong there? what does the compiler mean by that? and why does the poitner version works?

many thanks! :)

As you've discovered, the compiler needs to see the full definition of a class before an instance of it can be constructed (it needs to know how big the object will be). The pointer version works because it's just a pointer not an actual instance.

ahh., so how will i remedy the problem?

Something like -

//file 1

#include "file2"

CLASS A
{
...
B b;
};

hiya, still same error, :)