#include <iostream>
 #include <memory>

 using std::cout;
 using std::endl;
 using std::weak_ptr;
 using std::shared_ptr;

 struct Son;
 struct Daughter;

 struct Mother{
   ~Mother(){cout << "Mother gone" << endl;}
   void setSon(const shared_ptr<Son> s ){
     mySon=s;
   }
   void setDaughter(const shared_ptr<Daughter> d ){
     myDaughter=d;
   }
   shared_ptr<const Son> mySon;
   weak_ptr<const Daughter> myDaughter;
 };

 struct Son{
   Son(shared_ptr<Mother> m):myMother(m){}
   ~Son(){cout << "Son gone" << endl;}
   shared_ptr<const Mother> myMother;
 };

 struct Daughter{
   Daughter(shared_ptr<Mother> m):myMother(m){}
   ~Daughter(){cout << "Daughter gone" << endl;}
   shared_ptr<const Mother> myMother;
 };

 int main(){
   cout << endl;
   {
     shared_ptr<Mother> mother= shared_ptr<Mother>( new Mother);
     shared_ptr<Son> son= shared_ptr<Son>( new Son(mother) );
     shared_ptr<Daughter> daugher= shared_ptr<Daughter>( new Daughter(mother) );
     mother->setSon(son);
     mother->setDaughter(daugher);
   }
   cout << endl;
 }