Most of the example should be obvious. The use of iterators requires some
explanation. An iterator is an object that is used to iterate over all
elements of some other object. The iterator hides the exact structure of
this other object. It doesn't matter whether the other object has a list
structure, a tree structure, an acyclic graph structure or something else:
the iterator is always used in the same way. With the hush ADT's, an
interator is created in the following manner:
iter<element-type>
iterator-name = object-to-be-iterated-over
;
The element type reflects the type of elements the iterator will
return:
iterating over a `split' string will result in seperate strings, iterating
over a list of integers will result in seperate integers, etc. The
assignment from an object to an iterator tells the iterator over which
object it should iterate. Each time the function operator() is
called, it will return a pointer to the next element. When there is
no next element, operator() will return a null-pointer (0 or
NULL).