Where to delete an object created by factory?

Question

If I have a factory, that creates an object and returns a pointer to it, what will be a better way to delete it:

By delete call in the \"user\" code, or by

Answer 1

The following code provides an opportunity not to think about who should remove the newly created object.

class FooFactory
{
public:
    static std::auto_ptr CreateInstance();
};

// transmit ownership of created object from factory to 'a' variable
std::auto_ptr a = FooFactory::CreateInstance();
// using the created object is not required
FooFactory::CreateInstance();