VB.Net - Queue

It represents a first-in, first-out collection of object. It is used when you need a first-in, first-out access of items. When you add an item in the list, it is called enqueue, and when you remove an item, it is called deque.

Properties and Methods of the Queue Class

The following table lists some of the commonly used properties of the Queue class −

Sr.No Property & Description
1

Count

Gets the number of elements contained in the Queue.

The following table lists some of the commonly used methods of the Queue class −

Sr.No. Method Name & Purpose
1

Public Overridable Sub Clear

Removes all elements from the Queue.
2

Public Overridable Function Contains (obj As Object) As Boolean

Determines whether an element is in the Queue.
3

Public Overridable Function Dequeue As Object

Removes and returns the object at the beginning of the Queue.
4

Public Overridable Sub Enqueue (obj As Object)

Adds an object to the end of the Queue.
5

Public Overridable Function ToArray As Object()

Copies the Queue to a new array.
6

Public Overridable Sub TrimToSize

Sets the capacity to the actual number of elements in the Queue.

Example

The following example demonstrates use of Queue −

Module collections
   Sub Main()
      Dim q As Queue = New Queue()
      q.Enqueue("A")
      q.Enqueue("M")
      q.Enqueue("G")
      q.Enqueue("W")
      Console.WriteLine("Current queue: ")
      Dim c As Char
      
      For Each c In q
         Console.Write(c + " ")
      Next c
      Console.WriteLine()
      q.Enqueue("V")
      q.Enqueue("H")
      Console.WriteLine("Current queue: ")
      
      For Each c In q
         Console.Write(c + " ")
      Next c
      Console.WriteLine()
      Console.WriteLine("Removing some values ")
      Dim ch As Char
      ch = q.Dequeue()
      Console.WriteLine("The removed value: {0}", ch)
      ch = q.Dequeue()
      Console.WriteLine("The removed value: {0}", ch)
      Console.ReadKey()
   End Sub
End Module

When the above code is compiled and executed, it produces the following result −

Current queue: 
A M G W 
Current queue: 
A M G W V H 
Removing some values
The removed value: A
The removed value: M
vb.net_collections.htm
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