Visual Basic.NET How to Program (PDF)

Chapter 23 Data Structures and Collections 1159
32
33 ' use method Dequeue to remove items from queue
34 Dim removedObject As Object = Nothing
35
36 ' remove items from queue
37 Try
38
39 ' dequeue item and output removed item
40 While True
41 removedObject = queue.Dequeue()
42 Console.WriteLine(removedObject & " dequeue")
43 queue.Print()
44 End While
45
46 ' if exception occurs, print stack trace
47 Catch emptyListException As EmptyListException
48 Console.Error.WriteLine(emptyListException.StackTrace)
49 End Try
50
51 End Sub ' Main
52
53 End Module ' modQueueTest
The queue is: True
The queue is: True $
The queue is: True $ 34567
The queue is: True $ 34567 hello
True dequeue
The queue is: $ 34567 hello
$ dequeue
The queue is: 34567 hello
34567 dequeue
The queue is: hello
hello dequeue
Empty queue
at LinkedListLibrary.CList.RemoveFromFront() in
C:\books\2001\vbhtp2\ch23\Examples\Fig23_04\LinkedListLibrary\List.vb:line
64
at QueueInheritanceLibrary.CQueueInheritance.Dequeue() in
C:\books\2001\vbhtp2\ch23\Examples\Fig23_15\QueueInheritanceLibrary\QueueInheritance.vb:line
25
at QueueTest.modQueueInheritanceTest.Main() in
C:\books\2001\vbhtp2\ch23\Examples\Fig23_16\QueueTest\QueueTest.vb:
line 41
Fig. 23.16 Queue-by-inheritance test (part 2 of 2).