Classes

class TimeStamp; // stores a time stamp
class fileParser; // parses text files for tag=value (or tag="value") cases
class HTMLPage : public fileParser; // stores an HTML page
class URL; [contains HTMLPage object] // retrieves an HTML page
class Vertex; // public virtual class for a vertex
class VertexURL : public virtual Vertex; [contains URL] // implements a vertex
class Arc; [contains two Vertex objects] // arc 
class Digraph; [contains a list of arcs and a timestamp] // graph

The diagram below shows the class interactions.