Graph Component Insertion and Removal

The following Graph member functions are defined for insertion and removal of Vertex and Edge components in both the generic and user-derived Graph types:

       int insert(Vertex* v);
       int insert(Edge* e);
       int remove(Vertex* v);
       int remove(Edge* e);

In our example, for a Module m and Transport_Time t, the following operations are legal:

       widget.insert(&m);
       widget.remove(&t);
       etc.

The Graph is not changed and the return value is false if any of the following three conditions exist:

• an insert or remove is attempted for a non-existent Vertex or Edge (i.e., the pointer value is 0)

• an insert is attempted for a Vertex or Edge that is currently in the Graph

• a remove is attempted for a Vertex or Edge that has not been previously inserted into the Graph

Note that removing a Vertex or Edge from a Graph does not destroy it; likewise, inserting a Vertex or Edge into a Graph does not create it: static or dynamic creation of Vertices and Edges must take place prior to insertion into the Graph.