In c++ how can I make class to recognize structures without including the header?

Question

Hello I have class AA.h and inside I have defined structure:

#include "BB.h"

Struct  foo{

};

Class AA 
{
…
void funa()
{
    BB bb;
    foo f;
    bb.func(f);
}
….
};

My question is do I have to include the AA.h also in the BB.h file so it will recognize the foo struct or there is something else I can do ?

Answer 1

Seems simplest is to create a header for your struct then include it in both your AA and BB.

#ifndef __FOO__H__
#define __FOO__H__
struct foo {

};
#endif

Answer 2

I guess you want to use foo in BB.h . But you can not include AA.h in BB.h as it will introduce a cyclic dependency and the compilation will fail. The simplest way to solve this is to provide the implementation of A::funa in a separate source file (normally with .cpp extension). You just need to declare funa(); in the header file without any implementation. If you do this, then there is no need to include BB.h in AA.h (You need to include BB.h in AA.cpp ) thus avoiding the cyclic dependency.