#include <vector>

class A;
class B;

class A {
  std::vector <B*> list_of_b;
public:
  A();
  void MethodOfA();
};

class B {
  long long element;
public:
  B();
  B* AddOne();
};

A::A() {}

void A::MethodOfA() {
  std::vector <B*> _temp;
  _temp.reserve(list_of_b.size());
  std::for_each(list_of_b.begin(), list_of_b.end(), [_temp](B& pointer_to_b) {_temp.push_back(pointer_to_b->AddOne());});
}

B::B() {element = 1;}

B* B::AddOne() {
  B* new_element = new B();
  ++(new_element->element);
  return new_element;
}