Circular depediance

main.cpp

#include <iostream>

class Barney;

class Fred{
public:
  void tada(){
    std::cout << "tada" << std::endl;
  }
private:
    Barney* y;
};

class Barney{
public:
  void method(){
    x->tada();
  }
  
private:
  Fred* x;
};


int main(){
  Barney b;
  b.method();
}