I have a problem with recursive imports in C++. I have this 2 classes:
//File A.h
#include "B.h"
class A{
public:
A(){};
void doA(B b){ b.doB(); }
}//File B.h
#include "A.h"
class B{
public:
B(){};
void doB(A a){ a.doA(); }
}I tried to use forward declarations but it doesn't work because i call methods "doA" and "doB" so I cant use forward declarations.
Do someone know what can I do to compile it?
Thank you!
Jump to PostAre you macro protecting your header files?
#ifndef _SOME_HEADER #define _SOME_HEADER class SomeClass{...}; #endifor
#pragma once class SomeClass{...};
Jump to PostWhat's the compiler error look like?
Are you macro protecting your header files?
#ifndef _SOME_HEADER
#define _SOME_HEADER
class SomeClass{...};
#endifor
#pragma once
class SomeClass{...};Yes, I have
#ifndef _SOME_HEADER
#define _SOME_HEADER
....
#endifin all my classes.
What i dont undestand is why i can't find a solution in the web, because i think it's a very common problem....
What's the compiler error look like?
the problem is the chicken and the egg paradox. what comes first in your code A or B?. if A is first and A uses B then the compiler goes to B to find out what B is but B has A in it and A isn't finished so it doesn't know what A is yet either. the same thing will happen if B is first. unfortunately there is no solution for this problem. it just isn't possible in c++ right now. you can have A have a B as long as B doesn't have an A in it or the other way around with B but A cant have B when B has A in it. i really hope I'm making sense
Thank you, but i have just solved the problem.
I used forward references in A.h and B.h, and used includes in A.cpp and B.cpp
I don't know if this is standard C, but in C++ Builder works.
//File A.h
#include "B.h"
class B; // pre-declare B class
class A {
public:
A(){};
void doA(B b){ b.doB(); }
}//File B.h
#include "A.h"
class A; // pre-declare A class
class B {
public:
B(){};
void doB(A a){ a.doA(); }
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