Enqueue, Dequeue and Peek : Queue « Collections « VB.Net Tutorial






Imports System
 Imports System.Collections
 Class Tester
     Public Sub Run( )
     End Sub 'Run

     Public Shared Sub DisplayValues(ByVal myCollection As IEnumerable)
         Dim myEnumerator As IEnumerator = myCollection.GetEnumerator( )
         While myEnumerator.MoveNext( )
             Console.WriteLine("{0} ", myEnumerator.Current)
         End While
         Console.WriteLine( )
     End Sub 'DisplayValues

     Shared Sub Main( )
         Dim intQueue As New Queue( )

         ' populate the array
         Dim i As Integer
         For i = 0 To 4
             intQueue.Enqueue((i * 5))
         Next i

         ' Display the Queue.
         Console.WriteLine("intQueue values:")
         DisplayValues(intQueue)

         ' Remove an element from the queue.
         Console.WriteLine("(Dequeue) {0}", intQueue.Dequeue( ))

         ' Display the Queue.
         Console.WriteLine("intQueue values:")
         DisplayValues(intQueue)

         ' Remove another element from the queue.
         Console.WriteLine("(Dequeue) {0}", intQueue.Dequeue( ))

         ' Display the Queue.
         Console.WriteLine("intQueue values:")
         DisplayValues(intQueue)

         ' View the first element in the
         ' Queue but do not remove.
         Console.WriteLine("(Peek)   {0}", intQueue.Peek( ))

         ' Display the Queue.
         Console.WriteLine("intQueue values:")
         DisplayValues(intQueue)
     End Sub 'Main
 End Class 'Tester
intQueue values:
0
5
10
15
20

(Dequeue) 0
intQueue values:
5
10
15
20

(Dequeue) 5
intQueue values:
10
15
20

(Peek)   10
intQueue values:
10
15
20








8.26.Queue
8.26.1.Queue
8.26.2.Enqueue, Dequeue and Peek
8.26.3.Queue.Enqueue and ToArray
8.26.4.Create a copy of the queue, using the ToArray method and the constructor that accepts an IEnumerable(Of T).
8.26.5.A queue can be enumerated without disturbing its contents.
8.26.6.Dequeuing,Peek and Dequeuing again
8.26.7.Copy the elements of the queue, starting at the middle of the array.
8.26.8.Queue.Contains
8.26.9.The Contains method is used to show that the string "four" is in the first copy of the queue