Unique pointers provide exclusive ownership of an object, preventing copying but allowing movement. They automatically release memory when the pointer goes out of scope, making them ideal for single ownership scenarios and resources like file handles. Shared pointers enable multiple owners of an object through reference counting. While flexible, they can introduce performance overhead and potential circular reference issues. Careful consideration is essential when using shared pointers, especially in complex object structures. Weak pointers do not own the object they reference but instead observe its lifetime. Primarily used to break circular dependencies between shared pointers, weak pointers provide a way to check if a shared pointer still exists without affecting ownership.
Polymorphism is the ability of different objects to react in an individual manner to the same message. This notion was imported from natural languages. For example, the verb "to close" means different things when applied to different objects. Closing a door, closing a bank account, or closing a program's window are all different actions; their exact meaning is determined by the object on which the action is performed. Most object-oriented languages implement polymorphism only in the form of virtual functions. But C++ has two more mechanisms of static (meaning: compile-time) polymorphism: Operator overloading. Applying the += operator to integers or string objects, for example, is interpreted by each of these objects in an individual manner. Obviously, the underlying implementation of += differs in every type. Yet, intuitively, we can predict what results are. Templates. A vector of integers, for example, reacts differently from a vector of string objects when it receives