I need to include two header files to each other not using forward declaration cause get "incomplete type" error

Question

I need to include two header files to each other but I have trouble doing this. Is there any way except using forward declaration and template to do this ? or I'm not allowed to do it in c++?

here is what I want to do:

// A.hpp file
#ifndef H_A_H
#define H_A_H
#include "B.hpp"
class A {
private:
  vector<B*> b;
public:
  void function() {
  // using methods of B
  }
};
#endif


// B.hpp file
#ifndef H_B_H
#define H_B_H
#include "A.hpp"
class B {
private:
  vector<A*> a;
public:
  void function() {
  // using methods of A
  }
};
#endif

Answer 1

You can't include two header files to each other. There should be forward declaration in one of the files and function definition has to be pushed to .cpp file where you can include the header file.

// HeaderA.h file
#ifndef H_A_H
#define H_A_H
#include "HeaderB.h"
class A {
private:
  int b;
public:
  void function() {
  // using methods of B
      B b;
      b.function();
  }
};
#endif

// HeaderB.h file
#ifndef H_B_H
#define H_B_H

class A;

class B {
private:
  int a;
public:
  void function();
};
#endif

// Main.cpp
#include "HeaderA.h"
#include "HeaderB.h"

 void B::function()
 {
  // using methods of A
      A a;
      a.function();
 }

int _tmain(int argc, _TCHAR* argv[])
{
    return 0;
}