BinaryTreeTraversals.vb

Module Module1

    Class Node
        Public Key As Integer
        Public Left, Right As Node

        Sub New(Item As Integer)
            Key = Item
            Left = Nothing
            Right = Nothing
        End Sub

    End Class

    Class BinaryTree
        Public Root As Node
        Sub New()
            Root = Nothing
        End Sub

        Sub PrintPreorder(Node As Node)
            If Node Is Nothing Then
                Return
            End If
            Console.WriteLine(Node.Key)
            PrintPreorder(Node.Left)
            PrintPreorder(Node.Right)
        End Sub

        Sub PrintInorder(Node As Node)
            If Node Is Nothing Then
                Return
            End If
            PrintInorder(Node.Left)
            Console.WriteLine(Node.Key)
            PrintInorder(Node.Right)
        End Sub

        Sub PrintPostOrder(Node As Node)
            If Node Is Nothing Then
                Return
            End If
            PrintPostOrder(Node.Left)
            PrintPostOrder(Node.Right)
            Console.WriteLine(Node.Key)
        End Sub

        Sub PrintPreorder()
            PrintPreorder(Root)
        End Sub

        Sub PrintInorder()
            PrintInorder(Root)
        End Sub

        Sub PrintPostOrder()
            PrintPostOrder(Root)
        End Sub
    End Class

    Sub Main()
        Dim Tree As BinaryTree = New BinaryTree()
        Tree.Root = New Node(1)
        Tree.Root.Left = New Node(2)
        Tree.Root.Right = New Node(3)
        Tree.Root.Left.Left = New Node(4)
        Tree.Root.Left.Right = New Node(5)

        Tree.PrintPreorder()
        Console.WriteLine("------Inorder-------")
        Tree.PrintInorder()
        Console.WriteLine("------Postorder-------")
        Tree.PrintPostOrder()
        Console.ReadLine()
    End Sub

End Module