#include <memory>
#include <iostream>

int main()
{
  auto p = std::make_shared<double>(3.1415);
  decltype(p) q =  p;
  std::shared_ptr<double> r = q;
	
  std::cout << r.use_count() << " Referenzen\n";

  *p.get()  = 42;	        // roher Zeiger: &*p
  if (q) *q = 2.71828; 
	
  std::cout << *r << '\n';
  p = nullptr;
  std::cout << *r << '\n';
  q.reset();

  std::cout << *r << '\n';
  std::cout << "Einzige Referenz: " << std::boolalpha << r.unique() << '\n';
}