C++ Primer Plus

Selecting a Smart Pointer

Which pointer type should you use? If the program uses more than one pointer to an object, shared_ptr is your choice. For instance, you may have an array of pointers and use some auxiliary pointers to identify particular elements, such as the largest and the smallest. Or you could have two kinds of objects that contain pointers to the same third object. Or you might have an STL container of pointers. Many of the STL algorithms include copy or assignment operations that will work with shared_ptr but not with unique_ptr (you’ll get a compiler warning) or auto_ptr (you’ll get undefined behavior). If your compiler doesn’t offer shared_ptr, you can get a version from the Boost library.

If the program doesn’t need multiple ...