Queue: Enqueue |
Adds an item to the tail of the Queue, expanding the queue as necessary.
Public Sub Enqueue( ByRef Value As Variant )
The capacity of a Queue is the number of elements the Queue can hold. As elements are added to a Queue, the capacity is automatically increased as required through reallocation. The capacity can be decreased by calling TrimToSize.
If Count is less than the capacity of the internal array, this method is an O(1) operation. If the internal array needs to be reallocated to accommodate the new element, this method becomes an O(n) operation, where n is Count.
The following example shows how to add elements to the Queue, remove elements from the Queue, or view the element at the beginning of the Queue.
Public Sub Main() Dim MyQ As New Queue MyQ.Enqueue "The" MyQ.Enqueue "quick" MyQ.Enqueue "brown" MyQ.Enqueue "fox" ' Display the Queue Debug.Print "Queue values:"; PrintValues MyQ ' Removes an element from the queue. Debug.Print "(Dequeue) " & MyQ.Dequeue ' Displays the queue. Debug.Print "Queue values:"; PrintValues MyQ ' Removes another element from the queue. Debug.Print "(Dequeue) " & MyQ.Dequeue ' Displays the queue. Debug.Print "Queue values:"; PrintValues MyQ ' Views the first element in the queue but does not remove it. Debug.Print "(Peek) " & MyQ.Peek ' Displays the queue. Debug.Print "Queue values:"; PrintValues MyQ End Sub Private Sub PrintValues(ByVal MyCollection As IEnumerable) Dim Item As Variant For Each Item In MyCollection Debug.Print " " & Item; Next Debug.Print End Sub ' This example code produces the following output. ' ' Queue values: The quick brown fox ' (Dequeue) The ' Queue values: quick brown fox ' (Dequeue) quick ' Queue Values: brown fox ' (Peek) brown ' Queue Values: brown fox