/*intersection ........... */
void Intersection (Queue q,Queue r, Queue &s)
{
Q_entry x, y;
Queue temp;
while(!q.empty())
{
q.retrieve(x);
while(!r.empty())
{
r.retrieve(y);
if(x==y)
s.append(x);
r.serve();
temp.append(y);
}
r = temp;
q.serve();
}
}
