The operators new and delete replace the C function calls malloc and free. Function malloc does not provide any method of initializing allocated block of memory. Keyword static is used for declarations. Static members must be initialized one at file scope. Have no this pointer since static members and functions exist independent of any objects of a class.
Access specifiers-public, private, and protected.
Stacks are implemented via arrays which can be hidden from their clients. Users may happen to know the details of how a class is implemented, user should not write code that relies on these details. The implementation of a particular class can be altered or replaced without affecting rest of the system as long as the public interface does not change. Iterators are commonly associated with container classes. Similar to a bookmark, once written it is easy to fined the next element.