Smart Pointers

• All over the place you see warnings not to use raw pointers.
  • They are a challenge.
  • Error prone
  • And there is a better way.
• Consider badPointer.cpp
  • This doesn't have to be done in the constructor.
• Consider goodPointer.cpp
  • This also doesn't have to be in the constructor.
• Unique Pointers
  • a reference
  • Examples in
    • ArrayT.h
    • ArrayT.cpp
  • Also read the book starting on page 182.
  • include <memory>
  • unique_ptr<type> var
  • unique_ptr<type> var(size)
  • Only one thing may point to this memory at a time.
  • Used the same way (->, *, and [])
  • make_unique<type>
  • make_unique<type>(int size)
  • reference
  • reset() will free the pointer.
    • Can take an argument, in which case it will point at that argument.
  • move(ptr) moves the unique pointer from variable to another.
    • The source is set to nullptr.
  • swap(ptr)
  • get() can be used to get to the underlying raw pointer.
  • release() the pointer no longer manages the memory.
• The code also uses an overloaded [] opperator
  • Threre are two cases of this

    • int & operator[](size_t i);
      const int & operator[](size_t i) const;

    • The first returns a reference to an element.
      • This is for use on the left hand side
      • IE you can assign to it.
    • The second just returns a copy
    • Note the difference in the use of const in the prototypes
      • The trailing const is the one that makes the difference.
  • The same is true with the At member function.