template <typename T>
struct deleter {
  void operator()(T* ptr) {
    delete ptr;
  }
};



struct S {
  int* p = new int(3);
  int x;

  S(int el) : x(el) {}

  ~S() {
    delete p;
  }
};

int main() {
//  void* p = ::operator new(sizeof(std::string));
//  new(p) std::string(3, 'a');
//  new(p) std::string(5, 'b');
//  ::operator delete(p);

//  std::string* p = new std::string(4, 'a');
//  std::cout << *p << " ";
//  new(p) std::string(3, 'b');
//  std::cout << *p;
//  delete p;

  S* p = new S(4);

//  deleter<S> del;
//  del.operator()(p);

  std::cout << p->x << " ";
  new(p) S(5);
  std::cout << p->x;
  delete p;
}

#include <iostream>

template <class Arg>
Arg sum(Arg arg) { return arg; }

template <class First, class... Other>
auto sum(First first, Other... other)
{
  return first + sum(other...);
}

int main() {
  std::cout << sum(1, 3, 4, 5);
}