Mustakims awesome nothing

Module Module1

    Const NULLPOINTER = -1
    Structure TreeNode
        Dim Data As String
        Dim LeftPointer, RightPointer As Integer
    End Structure

    Dim Tree(7) As TreeNode
    Dim RootPointer As Integer
    Dim FreePtr As Integer

    Sub InitialiseTree()
        RootPointer = NULLPOINTER
        FreePtr = 0
        For Index = 0 To 7
            Tree(Index).LeftPointer = Index + 1
            Tree(Index).RightPointer = NULLPOINTER
            Tree(Index).Data = " "
        Next
        Tree(7).LeftPointer = NULLPOINTER

    End Sub

    Function FindNode(SearchItem) As Integer
        Dim ThisNodePtr As Integer
        ThisNodePtr = RootPointer
        Try
            Do While ThisNodePtr <> NULLPOINTER And
                Tree(ThisNodePtr).Data <> SearchItem
                If Tree(ThisNodePtr).Data > SearchItem Then
                    ThisNodePtr = Tree(ThisNodePtr).LeftPointer
                Else
                    ThisNodePtr = Tree(ThisNodePtr).RightPointer
                End If
            Loop
        Catch ex As Exception

        End Try
        Return ThisNodePtr
    End Function

    Sub InsertNode(NewItem)
        Dim NewNodePtr, ThisNodePtr, PreviousNodePtr As Integer
        Dim TurnedLeft As Boolean
        If FreePtr <> NULLPOINTER Then
            NewNodePtr = FreePtr
            Tree(NewNodePtr).Data = NewItem
            FreePtr = Tree(FreePtr).LeftPointer
            Tree(NewNodePtr).LeftPointer = NULLPOINTER
            If RootPointer = NULLPOINTER Then
                RootPointer = NewNodePtr
            Else
                ThisNodePtr = RootPointer
                Do While ThisNodePtr <> NULLPOINTER
                    PreviousNodePtr = ThisNodePtr
                    If Tree(ThisNodePtr).Data > NewItem Then
                        TurnedLeft = True
                        ThisNodePtr = Tree(ThisNodePtr).LeftPointer
                    Else
                        TurnedLeft = False
                        ThisNodePtr = Tree(ThisNodePtr).RightPointer
                    End If
                Loop
                If TurnedLeft Then
                    Tree(PreviousNodePtr).LeftPointer = NewNodePtr
                Else
                    Tree(PreviousNodePtr).RightPointer = NewNodePtr
                End If
            End If
        Else
            Console.WriteLine("no space for more data")
        End If
    End Sub

    Sub TraverseTree(RootPointer)
        If RootPointer <> NULLPOINTER Then
            TraverseTree(Tree(RootPointer).LeftPointer)
            Console.WriteLine(Tree(RootPointer).Data)
            TraverseTree(Tree(RootPointer).RightPointer)
        End If
    End Sub

    Function GetOption()
        Dim Choice As Char
        Console.WriteLine("1: add data")
        Console.WriteLine("2: find data")
        Console.WriteLine("3: traverse tree")
        Console.WriteLine("4: end program")
        Console.WriteLine("Enter your choice: ")
        Choice = Console.ReadLine
        Return (Choice)
    End Function

    Sub Main()
        Dim Choice As Char
        Dim Data As String
        Dim ThisNodePtr As Integer

        InitialiseTree()
        Choice = GetOption()
        Do While Choice <> "4"
            Select Case Choice
                Case "1"
                    Console.WriteLine("Enter the value: ")
                    Data = Console.ReadLine()
                    InsertNode(Data)
                    TraverseTree(RootPointer)
                Case "2"
                    Console.WriteLine("Enter search value: ")
                    Data = Console.ReadLine()
                    ThisNodePtr = FindNode(Data)
                    If ThisNodePtr = NULLPOINTER Then
                        Console.WriteLine("Value not found")
                    Else
                        Console.WriteLine("value found at: " & ThisNodePtr)
                    End If
                    Console.WriteLine(RootPointer & " " & FreePtr)
                    For i = 0 To 7
                        Console.WriteLine(i & " " & Tree(i).LeftPointer & " " & Tree(i).Data & " " & Tree(i).RightPointer)
                    Next
                Case "3"
                    TraverseTree(RootPointer)
            End Select
            Choice = GetOption()

        Loop
    End Sub

End Module