VB.Net Tutorial/Collections/Your Tree

Define your own binary tree

<source lang="vbnet">Public Class TreeNode

  Private mLeftNode As TreeNode
  Private mData As Integer
  Private mRightNode As TreeNode
  Public Sub New(ByVal nodeData As Integer)
     mData = nodeData
     mRightNode = Nothing
     LeftNode = Nothing
  End Sub " New
  Public Property LeftNode() As TreeNode
     Get
        Return mLeftNode
     End Get
     Set(ByVal value As TreeNode)
        mLeftNode = value
     End Set
  End Property
  
  Public Property Data() As Integer
     Get
        Return mData
     End Get
     Set(ByVal value As Integer)
        mData = value
     End Set
  End Property " Data
  Public Property RightNode() As TreeNode
     Get
        Return mRightNode
     End Get
     Set(ByVal value As TreeNode)
        mRightNode = value
     End Set
  End Property
  
  Public Sub Insert(ByVal insertValue As Integer)
     If insertValue < mData Then
        If mLeftNode Is Nothing Then
           LeftNode = New TreeNode(insertValue)
        Else
           LeftNode.Insert(insertValue)
        End If
     ElseIf insertValue > mData Then
        If RightNode Is Nothing Then
           RightNode = New TreeNode(insertValue)
        Else
           RightNode.Insert(insertValue)
        End If
     End If
  End Sub

End Class Public Class Tree

  Private root As TreeNode
  Public Sub New()
     root = Nothing
  End Sub " New
  Public Sub InsertNode(ByVal insertValue As Integer)
     SyncLock (Me)
        If root Is Nothing Then
           root = New TreeNode(insertValue)
        Else 
           root.Insert(insertValue)
        End If
     End SyncLock
  End Sub
  
  Public Sub PreorderTraversal()
     SyncLock (Me)
        DoTraversal(root)
     End SyncLock
  End Sub
  Private Sub DoTraversal(ByVal node As TreeNode)
     If node Is Nothing Then
        Return
     End If
     Console.Write(node.Data & " ")
     DoTraversal(node.LeftNode)
     DoTraversal(node.RightNode)
  End Sub
  
  Public Sub InorderTraversal()
     SyncLock (Me)
        DoInorder(root)
     End SyncLock
  End Sub 
  Private Sub DoInorder(ByVal node As TreeNode)
     If node Is Nothing Then
        Return
     End If
     DoInorder(node.LeftNode)
     Console.Write(node.Data & " ")
     DoInorder(node.RightNode)
  End Sub " DoInorder
  Public Sub PostorderTraversal()
     SyncLock (Me)
        DoPostorder(root)
     End SyncLock
  End Sub
  
  Private Sub DoPostorder(ByVal node As TreeNode)
     If node Is Nothing Then
        Return
     End If
     DoPostorder(node.LeftNode)
     DoPostorder(node.RightNode)
     Console.Write(node.Data & " ")
  End Sub 

End Class Module modTreeTest

  Sub Main()
     Dim tree As Tree = New Tree()
     Dim insertValue As Integer
     Dim i As Integer
     Console.WriteLine("Inserting Values: ")
     Dim randomNumber As Random = New Random()
     For i = 1 To 10
        insertValue = randomNumber.Next(100)
        Console.Write(insertValue & " ")
        tree.InsertNode(insertValue)
     Next
     Console.WriteLine("Preorder Traversal")
     tree.PreorderTraversal()
     Console.WriteLine("Inorder Traversal")
     tree.InorderTraversal()
     Console.WriteLine("Postorder Traversal")
     tree.PostorderTraversal()
  End Sub

End Module</source>

Inserting Values:
17 20 77 11 86 68 51 23 62 80 Preorder Traversal
17 11 20 77 68 51 23 62 86 80 Inorder Traversal
11 17 20 23 51 62 68 77 80 86 Postorder Traversal
11 23 62 51 68 80 86 77 20 17 "