auto_ptr & share_ptr & unique_ptr

Using auto_ptr, you don’t need think about the memory deallocation, but there are also many arguments about it because of auto_ptr ownership translation.

void AutoPtrTest(void)
{
   std::auto_ptr<int> p1 (new int());
   //pass ownership
   std::auto_ptr<int> p2 = p1;
   std::cout << "p1 will raise exception:" << *p1 << std::endl;
   std::cout << "p2 is ok: " << *p2 << std::endl;
}

In C++11, the auto_ptr is deprecated. The shared_ptr and unique_ptr are designed which have more security and comprehensive.

void AutoPtrTest(void)
{
   std::auto_ptr<int> p1 (new int());
   //pass ownership
   std::auto_ptr<int> p2 = p1; //here has a warning in GCC
   //std::cout << "p1 will raise exception:" << *p1 << std::endl;
   std::cout << "p2 is ok: " << *p2 << std::endl;

   std::shared_ptr<int> s1 (new int());
   std::shared_ptr<int> s2 = s1; //share it. point to same address
   std::cout << "s1 is ok:" << *s1 << std::endl;
   std::cout << "s2 is ok: " << *s2 << std::endl;

   std::unique_ptr<int> u1 (new int());
  // std::unique_ptr<int> u2 = u1; //cannot be compiled
   std::cout << "u1 is ok:" << *u1 << std::endl;
  // std::cout << "s2 is ok: " << *s2 << std::endl;
}

In conclusion, auto_ptr could be replaced by shared_ptr or unique_ptr depending upon situation.