Hello,
In a Binary Search Tree I get the error : Object must be of type String
if I run the form only with the "Dim bstLidnummer As New BinarySearchTree"
it works fine.
Thanks for any help on this,
Benny
My BST-code lookes lokes this :
**************************************************
Class BST
**************************************************
Public Class BinarySearchTree
Private Class TreeNode
Private mData As IComparable
Private mLeftNode As TreeNode
Private mRightNode As TreeNode
Public Sub New(ByVal data As IComparable)
Me.mData = data
End Sub
Public ReadOnly Property Data() As IComparable
Get
Return Me.mData
End Get
End Property
Public Property LeftNode() As TreeNode
Get
Return Me.mLeftNode
End Get
Set(ByVal value As TreeNode)
Me.mLeftNode = value
End Set
End Property
Public Property RightNode() As TreeNode
Get
Return Me.mRightNode
End Get
Set(ByVal value As TreeNode)
Me.mRightNode = value
End Set
End Property
Public Sub Add(ByVal data As IComparable)
If data.CompareTo(Me.mData) <= 0 Then
If Me.mLeftNode Is Nothing Then
Me.mLeftNode = New TreeNode(data)
Else
Me.mLeftNode.Add(data)
End If
Else
If Me.mRightNode Is Nothing Then
Me.mRightNode = New TreeNode(data)
Else
Me.mRightNode.Add(data)
End If
End If
End Sub
End Class
Private mRoot As TreeNode
Public Sub Add(ByVal data As IComparable)
If mRoot Is Nothing Then
mRoot = New TreeNode(data)
Else
mRoot.Add(data)
End If
End Sub
Public Function Search(ByVal data As IComparable) As Object
Return Me.Search(data, Me.mRoot)
End Function
Private Function Search(ByVal data As IComparable, ByVal node As
TreeNode) As Object
If node Is Nothing Then
Return Nothing
Else
Dim result As Integer = data.CompareTo(node.Data) '****** this is
the error I get on this line :Object must be of type String.
If result = 0 Then
Return node.Data
ElseIf result < 0 Then
Return Me.Search(data, node.LeftNode)
Else
Return Me.Search(data, node.RightNode)
End If
End If
End Function
End Class
*****************************
The class Person
*****************************
Public Class Persoon
Inherits BusinessObject
Implements IComparable
Private mVnaam As String
Private mAnaam As String
Public Sub New(ByVal Vnaam As String, ByVal Anaam As String)
Me.mVnaam = Vnaam
Me.mAnaam = Anaam
End Sub
Public Property Vnaam() As String
Get
Return Me.mVnaam
End Get
Set(ByVal value As String)
mVnaam = value
End Set
End Property
Public Property Anaam() As String
Get
Return Me.mAnaam
End Get
Set(ByVal value As String)
Me.mAnaam = value
End Set
End Property
Public Overrides Function IsValid() As Boolean
If Me.isValidVnaam() And Me.isValidAnaam() Then
Return True
Else
Return False
End If
End Function
Private Function isValidVnaam() As Boolean
If Me.Vnaam.Trim.Length 0 Then
Return True
Else
Return False
End If
End Function
Private Function isValidAnaam() As Boolean
If Me.Anaam.Trim.Length 0 Then
Return True
Else
Return False
End If
End Function
Public Overloads Function CompareTo(ByVal obj As Object) As Integer
Implements System.IComparable.CompareTo
Return Me.mVnaam.CompareTo(CType(obj, Persoon).Vnaam)
End Function
End Class
**********************************
The Form :
**********************************
Public Class frmBinarySearchTree
Private Sub btnExecute_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnExecute.Click
Dim bstLedenLijst As New BinarySearchTree
Dim bstLidnummer As New BinarySearchTree
Dim txtOutput As String = ""
bstLidnummer.Add("5")
bstLidnummer.Add("2")
bstLidnummer.Add("1")
bstLidnummer.Add("4")
bstLidnummer.Add("3")
txtOutput = bstLidnummer.Search("3") & vbCrLf
bstLedenLijst.Add(New Persoon("Nicole", "Kidman"))
bstLedenLijst.Add(New Persoon("Jamie-Lee", "Curtis"))
bstLedenLijst.Add(New Persoon("Demi", "Moore"))
bstLedenLijst.Add(New Persoon("Julia", "Roberts"))
bstLedenLijst.Add(New Persoon("Andie", "MacDowell"))
txtOutput &= bstLedenLijst.Search("Demi") ' & vbCrLf
Me.txtOutput.Text = txtOutput
End Sub
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnExit.Click
Application.Exit()
End Sub
End Class 4 2151
BenCoo,
Interesting homework assignment; I miss those days...
Anyway to answer your question:
Dim bstLedenLijst As New BinarySearchTree
Dim bstLidnummer As New BinarySearchTree
Dim txtOutput As String = ""
bstLidnummer.Add("5")
txtOutput = bstLidnummer.Search("3") & vbCrLf
bstLedenLijst.Add(New Persoon("Nicole", "Kidman"))
txtOutput &= bstLedenLijst.Search("Demi") ' & vbCrLf
Ah! There's the Rub!
bstLedenLijst contains a collection of Persoon objects, you are attempting
to compare Persoon objects to a String object! You need to pass a Persoon
object to bstLedenLijst.Search. I would recommend you change
BinarySearchTree to a Generic class; changing this obscure runtime error
into an obvious compile time error!
Something like:
Public Class BinarySearchTree(Of T As IComparable)
Private Class TreeNode
Private mData As T
Private mLeftNode As TreeNode
Private mRightNode As TreeNode
Public Sub New(ByVal data As T)
Me.mData = data
End Sub
Public ReadOnly Property Data() As T
Get
Return Me.mData
End Get
End Property
Public Property LeftNode() As TreeNode
Get
Return Me.mLeftNode
End Get
Set(ByVal value As TreeNode)
Me.mLeftNode = value
End Set
End Property
Public Property RightNode() As TreeNode
Get
Return Me.mRightNode
End Get
Set(ByVal value As TreeNode)
Me.mRightNode = value
End Set
End Property
Public Sub Add(ByVal data As T)
If data.CompareTo(Me.mData) <= 0 Then
If Me.mLeftNode Is Nothing Then
Me.mLeftNode = New TreeNode(data)
Else
Me.mLeftNode.Add(data)
End If
Else
If Me.mRightNode Is Nothing Then
Me.mRightNode = New TreeNode(data)
Else
Me.mRightNode.Add(data)
End If
End If
End Sub
End Class
Private mRoot As TreeNode
Public Sub Add(ByVal data As T)
If mRoot Is Nothing Then
mRoot = New TreeNode(data)
Else
mRoot.Add(data)
End If
End Sub
Public Function Search(ByVal data As T) As Object
Return Me.Search(data, Me.mRoot)
End Function
Private Function Search(ByVal data As T, ByVal node As TreeNode) As
Object
If node Is Nothing Then
Return Nothing
Else
Dim result As Integer = data.CompareTo(node.Data) '****** this
is the error I get on this line :Object must be of type String.
If result = 0 Then
Return node.Data
ElseIf result < 0 Then
Return Me.Search(data, node.LeftNode)
Else
Return Me.Search(data, node.RightNode)
End If
End If
End Function
End Class
Then when you define your trees, you give the type of tree they are!
Dim bstLedenLijst As New BinarySearchTree(Of String)
Dim bstLidnummer As New BinarySearchTree(Of Persoon)
NOTE: You need VS 2005 for generics.
--
Hope this helps
Jay B. Harlow
..NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net
"BenCoo" <te******@hotmail.comwrote in message
news:CN**********************@phobos.telenet-ops.be...
Hello,
In a Binary Search Tree I get the error : Object must be of type String
if I run the form only with the "Dim bstLidnummer As New
BinarySearchTree"
it works fine.
Thanks for any help on this,
Benny
My BST-code lookes lokes this :
**************************************************
Class BST
**************************************************
Public Class BinarySearchTree
Private Class TreeNode
Private mData As IComparable
Private mLeftNode As TreeNode
Private mRightNode As TreeNode
Public Sub New(ByVal data As IComparable)
Me.mData = data
End Sub
Public ReadOnly Property Data() As IComparable
Get
Return Me.mData
End Get
End Property
Public Property LeftNode() As TreeNode
Get
Return Me.mLeftNode
End Get
Set(ByVal value As TreeNode)
Me.mLeftNode = value
End Set
End Property
Public Property RightNode() As TreeNode
Get
Return Me.mRightNode
End Get
Set(ByVal value As TreeNode)
Me.mRightNode = value
End Set
End Property
Public Sub Add(ByVal data As IComparable)
If data.CompareTo(Me.mData) <= 0 Then
If Me.mLeftNode Is Nothing Then
Me.mLeftNode = New TreeNode(data)
Else
Me.mLeftNode.Add(data)
End If
Else
If Me.mRightNode Is Nothing Then
Me.mRightNode = New TreeNode(data)
Else
Me.mRightNode.Add(data)
End If
End If
End Sub
End Class
Private mRoot As TreeNode
Public Sub Add(ByVal data As IComparable)
If mRoot Is Nothing Then
mRoot = New TreeNode(data)
Else
mRoot.Add(data)
End If
End Sub
Public Function Search(ByVal data As IComparable) As Object
Return Me.Search(data, Me.mRoot)
End Function
Private Function Search(ByVal data As IComparable, ByVal node As
TreeNode) As Object
If node Is Nothing Then
Return Nothing
Else
Dim result As Integer = data.CompareTo(node.Data) '****** this is
the error I get on this line :Object must be of type String.
If result = 0 Then
Return node.Data
ElseIf result < 0 Then
Return Me.Search(data, node.LeftNode)
Else
Return Me.Search(data, node.RightNode)
End If
End If
End Function
End Class
*****************************
The class Person
*****************************
Public Class Persoon
Inherits BusinessObject
Implements IComparable
Private mVnaam As String
Private mAnaam As String
Public Sub New(ByVal Vnaam As String, ByVal Anaam As String)
Me.mVnaam = Vnaam
Me.mAnaam = Anaam
End Sub
Public Property Vnaam() As String
Get
Return Me.mVnaam
End Get
Set(ByVal value As String)
mVnaam = value
End Set
End Property
Public Property Anaam() As String
Get
Return Me.mAnaam
End Get
Set(ByVal value As String)
Me.mAnaam = value
End Set
End Property
Public Overrides Function IsValid() As Boolean
If Me.isValidVnaam() And Me.isValidAnaam() Then
Return True
Else
Return False
End If
End Function
Private Function isValidVnaam() As Boolean
If Me.Vnaam.Trim.Length 0 Then
Return True
Else
Return False
End If
End Function
Private Function isValidAnaam() As Boolean
If Me.Anaam.Trim.Length 0 Then
Return True
Else
Return False
End If
End Function
Public Overloads Function CompareTo(ByVal obj As Object) As Integer
Implements System.IComparable.CompareTo
Return Me.mVnaam.CompareTo(CType(obj, Persoon).Vnaam)
End Function
End Class
**********************************
The Form :
**********************************
Public Class frmBinarySearchTree
Private Sub btnExecute_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnExecute.Click
Dim bstLedenLijst As New BinarySearchTree
Dim bstLidnummer As New BinarySearchTree
Dim txtOutput As String = ""
bstLidnummer.Add("5")
bstLidnummer.Add("2")
bstLidnummer.Add("1")
bstLidnummer.Add("4")
bstLidnummer.Add("3")
txtOutput = bstLidnummer.Search("3") & vbCrLf
bstLedenLijst.Add(New Persoon("Nicole", "Kidman"))
bstLedenLijst.Add(New Persoon("Jamie-Lee", "Curtis"))
bstLedenLijst.Add(New Persoon("Demi", "Moore"))
bstLedenLijst.Add(New Persoon("Julia", "Roberts"))
bstLedenLijst.Add(New Persoon("Andie", "MacDowell"))
txtOutput &= bstLedenLijst.Search("Demi") ' & vbCrLf
Me.txtOutput.Text = txtOutput
End Sub
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnExit.Click
Application.Exit()
End Sub
End Class
Doh!
Clicked send too soon. I had the trees backwards:
Dim bstLedenLijst As New BinarySearchTree(Of Persoon)
Dim bstLidnummer As New BinarySearchTree(Of String)
Of course this demonstrated the immediate & obvious compile time error I
suggested ;-)
--
Hope this helps
Jay B. Harlow
..NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net
"BenCoo" <te******@hotmail.comwrote in message
news:CN**********************@phobos.telenet-ops.be...
Hello,
In a Binary Search Tree I get the error : Object must be of type String
if I run the form only with the "Dim bstLidnummer As New
BinarySearchTree"
it works fine.
Thanks for any help on this,
Benny
My BST-code lookes lokes this :
**************************************************
Class BST
**************************************************
Public Class BinarySearchTree
Private Class TreeNode
Private mData As IComparable
Private mLeftNode As TreeNode
Private mRightNode As TreeNode
Public Sub New(ByVal data As IComparable)
Me.mData = data
End Sub
Public ReadOnly Property Data() As IComparable
Get
Return Me.mData
End Get
End Property
Public Property LeftNode() As TreeNode
Get
Return Me.mLeftNode
End Get
Set(ByVal value As TreeNode)
Me.mLeftNode = value
End Set
End Property
Public Property RightNode() As TreeNode
Get
Return Me.mRightNode
End Get
Set(ByVal value As TreeNode)
Me.mRightNode = value
End Set
End Property
Public Sub Add(ByVal data As IComparable)
If data.CompareTo(Me.mData) <= 0 Then
If Me.mLeftNode Is Nothing Then
Me.mLeftNode = New TreeNode(data)
Else
Me.mLeftNode.Add(data)
End If
Else
If Me.mRightNode Is Nothing Then
Me.mRightNode = New TreeNode(data)
Else
Me.mRightNode.Add(data)
End If
End If
End Sub
End Class
Private mRoot As TreeNode
Public Sub Add(ByVal data As IComparable)
If mRoot Is Nothing Then
mRoot = New TreeNode(data)
Else
mRoot.Add(data)
End If
End Sub
Public Function Search(ByVal data As IComparable) As Object
Return Me.Search(data, Me.mRoot)
End Function
Private Function Search(ByVal data As IComparable, ByVal node As
TreeNode) As Object
If node Is Nothing Then
Return Nothing
Else
Dim result As Integer = data.CompareTo(node.Data) '****** this is
the error I get on this line :Object must be of type String.
If result = 0 Then
Return node.Data
ElseIf result < 0 Then
Return Me.Search(data, node.LeftNode)
Else
Return Me.Search(data, node.RightNode)
End If
End If
End Function
End Class
*****************************
The class Person
*****************************
Public Class Persoon
Inherits BusinessObject
Implements IComparable
Private mVnaam As String
Private mAnaam As String
Public Sub New(ByVal Vnaam As String, ByVal Anaam As String)
Me.mVnaam = Vnaam
Me.mAnaam = Anaam
End Sub
Public Property Vnaam() As String
Get
Return Me.mVnaam
End Get
Set(ByVal value As String)
mVnaam = value
End Set
End Property
Public Property Anaam() As String
Get
Return Me.mAnaam
End Get
Set(ByVal value As String)
Me.mAnaam = value
End Set
End Property
Public Overrides Function IsValid() As Boolean
If Me.isValidVnaam() And Me.isValidAnaam() Then
Return True
Else
Return False
End If
End Function
Private Function isValidVnaam() As Boolean
If Me.Vnaam.Trim.Length 0 Then
Return True
Else
Return False
End If
End Function
Private Function isValidAnaam() As Boolean
If Me.Anaam.Trim.Length 0 Then
Return True
Else
Return False
End If
End Function
Public Overloads Function CompareTo(ByVal obj As Object) As Integer
Implements System.IComparable.CompareTo
Return Me.mVnaam.CompareTo(CType(obj, Persoon).Vnaam)
End Function
End Class
**********************************
The Form :
**********************************
Public Class frmBinarySearchTree
Private Sub btnExecute_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnExecute.Click
Dim bstLedenLijst As New BinarySearchTree
Dim bstLidnummer As New BinarySearchTree
Dim txtOutput As String = ""
bstLidnummer.Add("5")
bstLidnummer.Add("2")
bstLidnummer.Add("1")
bstLidnummer.Add("4")
bstLidnummer.Add("3")
txtOutput = bstLidnummer.Search("3") & vbCrLf
bstLedenLijst.Add(New Persoon("Nicole", "Kidman"))
bstLedenLijst.Add(New Persoon("Jamie-Lee", "Curtis"))
bstLedenLijst.Add(New Persoon("Demi", "Moore"))
bstLedenLijst.Add(New Persoon("Julia", "Roberts"))
bstLedenLijst.Add(New Persoon("Andie", "MacDowell"))
txtOutput &= bstLedenLijst.Search("Demi") ' & vbCrLf
Me.txtOutput.Text = txtOutput
End Sub
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnExit.Click
Application.Exit()
End Sub
End Class
Reviewing this, one more change:
Public Function Search(ByVal data As T) As T
Return Me.Search(data, Me.mRoot)
End Function
Private Function Search(ByVal data As T, ByVal node As TreeNode) As T
If node Is Nothing Then
Return Nothing
Else
Dim result As Integer = data.CompareTo(node.Data) '****** this
is the error I get on this line :Object must be of type String.
If result = 0 Then
Return node.Data
ElseIf result < 0 Then
Return Me.Search(data, node.LeftNode)
Else
Return Me.Search(data, node.RightNode)
End If
End If
Note that Search returns type T; this ensures that BinarySearchTree(Of T) is
type safe and performant. performant in that the data will not be boxed. (in
the case of BinarySearchTree(Of Integer))
Although I would recommend defining Search as:
Public Function Search(ByVal match As Predicate(Of T)) As T
Or even:
Public Delegate Function Predicate(Of T, V)(ByVal obj As T, ByVal value
As V) As Boolean
Public Function Search(Of V)(ByVal value As V, ByVal match As
Predicate(Of T, V)) As T
Which I will leave as an exercise for you to complete...
--
Hope this helps
Jay B. Harlow
..NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net
"Jay B. Harlow" <Ja************@tsbradley.netwrote in message
news:eI**************@TK2MSFTNGP04.phx.gbl...
BenCoo,
Interesting homework assignment; I miss those days...
Anyway to answer your question:
> Dim bstLedenLijst As New BinarySearchTree Dim bstLidnummer As New BinarySearchTree Dim txtOutput As String = ""
bstLidnummer.Add("5") txtOutput = bstLidnummer.Search("3") & vbCrLf
bstLedenLijst.Add(New Persoon("Nicole", "Kidman"))
txtOutput &= bstLedenLijst.Search("Demi") ' & vbCrLf
Ah! There's the Rub!
bstLedenLijst contains a collection of Persoon objects, you are attempting
to compare Persoon objects to a String object! You need to pass a Persoon
object to bstLedenLijst.Search. I would recommend you change
BinarySearchTree to a Generic class; changing this obscure runtime error
into an obvious compile time error!
Something like:
Public Class BinarySearchTree(Of T As IComparable)
Private Class TreeNode
Private mData As T
Private mLeftNode As TreeNode
Private mRightNode As TreeNode
Public Sub New(ByVal data As T)
Me.mData = data
End Sub
Public ReadOnly Property Data() As T
Get
Return Me.mData
End Get
End Property
Public Property LeftNode() As TreeNode
Get
Return Me.mLeftNode
End Get
Set(ByVal value As TreeNode)
Me.mLeftNode = value
End Set
End Property
Public Property RightNode() As TreeNode
Get
Return Me.mRightNode
End Get
Set(ByVal value As TreeNode)
Me.mRightNode = value
End Set
End Property
Public Sub Add(ByVal data As T)
If data.CompareTo(Me.mData) <= 0 Then
If Me.mLeftNode Is Nothing Then
Me.mLeftNode = New TreeNode(data)
Else
Me.mLeftNode.Add(data)
End If
Else
If Me.mRightNode Is Nothing Then
Me.mRightNode = New TreeNode(data)
Else
Me.mRightNode.Add(data)
End If
End If
End Sub
End Class
Private mRoot As TreeNode
Public Sub Add(ByVal data As T)
If mRoot Is Nothing Then
mRoot = New TreeNode(data)
Else
mRoot.Add(data)
End If
End Sub
Public Function Search(ByVal data As T) As Object
Return Me.Search(data, Me.mRoot)
End Function
Private Function Search(ByVal data As T, ByVal node As TreeNode) As
Object
If node Is Nothing Then
Return Nothing
Else
Dim result As Integer = data.CompareTo(node.Data) '****** this
is the error I get on this line :Object must be of type String.
If result = 0 Then
Return node.Data
ElseIf result < 0 Then
Return Me.Search(data, node.LeftNode)
Else
Return Me.Search(data, node.RightNode)
End If
End If
End Function
End Class
Then when you define your trees, you give the type of tree they are!
> Dim bstLedenLijst As New BinarySearchTree(Of String) Dim bstLidnummer As New BinarySearchTree(Of Persoon)
NOTE: You need VS 2005 for generics.
--
Hope this helps
Jay B. Harlow
.NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net
"BenCoo" <te******@hotmail.comwrote in message
news:CN**********************@phobos.telenet-ops.be...
>Hello,
In a Binary Search Tree I get the error : Object must be of type String
if I run the form only with the "Dim bstLidnummer As New BinarySearchTree" it works fine.
Thanks for any help on this,
Benny
My BST-code lookes lokes this : ************************************************* * Class BST ************************************************* * Public Class BinarySearchTree Private Class TreeNode Private mData As IComparable Private mLeftNode As TreeNode Private mRightNode As TreeNode
Public Sub New(ByVal data As IComparable) Me.mData = data End Sub
Public ReadOnly Property Data() As IComparable Get Return Me.mData End Get End Property
Public Property LeftNode() As TreeNode Get Return Me.mLeftNode End Get Set(ByVal value As TreeNode) Me.mLeftNode = value End Set End Property
Public Property RightNode() As TreeNode Get Return Me.mRightNode End Get Set(ByVal value As TreeNode) Me.mRightNode = value End Set End Property
Public Sub Add(ByVal data As IComparable) If data.CompareTo(Me.mData) <= 0 Then If Me.mLeftNode Is Nothing Then Me.mLeftNode = New TreeNode(data) Else Me.mLeftNode.Add(data) End If Else If Me.mRightNode Is Nothing Then Me.mRightNode = New TreeNode(data) Else Me.mRightNode.Add(data) End If End If End Sub End Class
Private mRoot As TreeNode
Public Sub Add(ByVal data As IComparable) If mRoot Is Nothing Then mRoot = New TreeNode(data) Else mRoot.Add(data) End If End Sub
Public Function Search(ByVal data As IComparable) As Object Return Me.Search(data, Me.mRoot) End Function
Private Function Search(ByVal data As IComparable, ByVal node As TreeNode) As Object
If node Is Nothing Then Return Nothing Else Dim result As Integer = data.CompareTo(node.Data) '****** this is the error I get on this line :Object must be of type String.
If result = 0 Then Return node.Data ElseIf result < 0 Then Return Me.Search(data, node.LeftNode) Else Return Me.Search(data, node.RightNode) End If End If
End Function End Class ***************************** The class Person ***************************** Public Class Persoon Inherits BusinessObject Implements IComparable
Private mVnaam As String Private mAnaam As String
Public Sub New(ByVal Vnaam As String, ByVal Anaam As String) Me.mVnaam = Vnaam Me.mAnaam = Anaam End Sub
Public Property Vnaam() As String Get Return Me.mVnaam End Get Set(ByVal value As String) mVnaam = value End Set End Property
Public Property Anaam() As String Get Return Me.mAnaam End Get Set(ByVal value As String) Me.mAnaam = value End Set End Property
Public Overrides Function IsValid() As Boolean If Me.isValidVnaam() And Me.isValidAnaam() Then Return True Else Return False End If End Function
Private Function isValidVnaam() As Boolean If Me.Vnaam.Trim.Length 0 Then Return True Else Return False End If End Function
Private Function isValidAnaam() As Boolean If Me.Anaam.Trim.Length 0 Then Return True Else Return False End If End Function
Public Overloads Function CompareTo(ByVal obj As Object) As Integer Implements System.IComparable.CompareTo Return Me.mVnaam.CompareTo(CType(obj, Persoon).Vnaam) End Function End Class ********************************** The Form : ********************************** Public Class frmBinarySearchTree
Private Sub btnExecute_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExecute.Click Dim bstLedenLijst As New BinarySearchTree Dim bstLidnummer As New BinarySearchTree Dim txtOutput As String = ""
bstLidnummer.Add("5") bstLidnummer.Add("2") bstLidnummer.Add("1") bstLidnummer.Add("4") bstLidnummer.Add("3") txtOutput = bstLidnummer.Search("3") & vbCrLf
bstLedenLijst.Add(New Persoon("Nicole", "Kidman")) bstLedenLijst.Add(New Persoon("Jamie-Lee", "Curtis")) bstLedenLijst.Add(New Persoon("Demi", "Moore")) bstLedenLijst.Add(New Persoon("Julia", "Roberts")) bstLedenLijst.Add(New Persoon("Andie", "MacDowell"))
txtOutput &= bstLedenLijst.Search("Demi") ' & vbCrLf
Me.txtOutput.Text = txtOutput
End Sub
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click Application.Exit() End Sub
End Class
Thank you for your quick response; I solved afther the poste was made the
promlem this way ..
Dim zoekPersoon As New Persoon(Me.txtZoek.Text, "")
Console.WriteLine(bstLedenLijst.Search(zoekPersoon ))
"Jay B. Harlow" <Ja************@tsbradley.netschreef in bericht
news:eI**************@TK2MSFTNGP04.phx.gbl...
BenCoo,
Interesting homework assignment; I miss those days...
Anyway to answer your question:
> Dim bstLedenLijst As New BinarySearchTree Dim bstLidnummer As New BinarySearchTree Dim txtOutput As String = ""
bstLidnummer.Add("5") txtOutput = bstLidnummer.Search("3") & vbCrLf
bstLedenLijst.Add(New Persoon("Nicole", "Kidman"))
txtOutput &= bstLedenLijst.Search("Demi") ' & vbCrLf
Ah! There's the Rub!
bstLedenLijst contains a collection of Persoon objects, you are attempting
to compare Persoon objects to a String object! You need to pass a Persoon
object to bstLedenLijst.Search. I would recommend you change
BinarySearchTree to a Generic class; changing this obscure runtime error
into an obvious compile time error!
Something like:
Public Class BinarySearchTree(Of T As IComparable)
Private Class TreeNode
Private mData As T
Private mLeftNode As TreeNode
Private mRightNode As TreeNode
Public Sub New(ByVal data As T)
Me.mData = data
End Sub
Public ReadOnly Property Data() As T
Get
Return Me.mData
End Get
End Property
Public Property LeftNode() As TreeNode
Get
Return Me.mLeftNode
End Get
Set(ByVal value As TreeNode)
Me.mLeftNode = value
End Set
End Property
Public Property RightNode() As TreeNode
Get
Return Me.mRightNode
End Get
Set(ByVal value As TreeNode)
Me.mRightNode = value
End Set
End Property
Public Sub Add(ByVal data As T)
If data.CompareTo(Me.mData) <= 0 Then
If Me.mLeftNode Is Nothing Then
Me.mLeftNode = New TreeNode(data)
Else
Me.mLeftNode.Add(data)
End If
Else
If Me.mRightNode Is Nothing Then
Me.mRightNode = New TreeNode(data)
Else
Me.mRightNode.Add(data)
End If
End If
End Sub
End Class
Private mRoot As TreeNode
Public Sub Add(ByVal data As T)
If mRoot Is Nothing Then
mRoot = New TreeNode(data)
Else
mRoot.Add(data)
End If
End Sub
Public Function Search(ByVal data As T) As Object
Return Me.Search(data, Me.mRoot)
End Function
Private Function Search(ByVal data As T, ByVal node As TreeNode) As
Object
If node Is Nothing Then
Return Nothing
Else
Dim result As Integer = data.CompareTo(node.Data) '****** this
is the error I get on this line :Object must be of type String.
If result = 0 Then
Return node.Data
ElseIf result < 0 Then
Return Me.Search(data, node.LeftNode)
Else
Return Me.Search(data, node.RightNode)
End If
End If
End Function
End Class
Then when you define your trees, you give the type of tree they are!
> Dim bstLedenLijst As New BinarySearchTree(Of String) Dim bstLidnummer As New BinarySearchTree(Of Persoon)
NOTE: You need VS 2005 for generics.
--
Hope this helps
Jay B. Harlow
.NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net
"BenCoo" <te******@hotmail.comwrote in message
news:CN**********************@phobos.telenet-ops.be...
>Hello,
In a Binary Search Tree I get the error : Object must be of type String
if I run the form only with the "Dim bstLidnummer As New BinarySearchTree" it works fine.
Thanks for any help on this,
Benny
My BST-code lookes lokes this : ************************************************* * Class BST ************************************************* * Public Class BinarySearchTree Private Class TreeNode Private mData As IComparable Private mLeftNode As TreeNode Private mRightNode As TreeNode
Public Sub New(ByVal data As IComparable) Me.mData = data End Sub
Public ReadOnly Property Data() As IComparable Get Return Me.mData End Get End Property
Public Property LeftNode() As TreeNode Get Return Me.mLeftNode End Get Set(ByVal value As TreeNode) Me.mLeftNode = value End Set End Property
Public Property RightNode() As TreeNode Get Return Me.mRightNode End Get Set(ByVal value As TreeNode) Me.mRightNode = value End Set End Property
Public Sub Add(ByVal data As IComparable) If data.CompareTo(Me.mData) <= 0 Then If Me.mLeftNode Is Nothing Then Me.mLeftNode = New TreeNode(data) Else Me.mLeftNode.Add(data) End If Else If Me.mRightNode Is Nothing Then Me.mRightNode = New TreeNode(data) Else Me.mRightNode.Add(data) End If End If End Sub End Class
Private mRoot As TreeNode
Public Sub Add(ByVal data As IComparable) If mRoot Is Nothing Then mRoot = New TreeNode(data) Else mRoot.Add(data) End If End Sub
Public Function Search(ByVal data As IComparable) As Object Return Me.Search(data, Me.mRoot) End Function
Private Function Search(ByVal data As IComparable, ByVal node As TreeNode) As Object
If node Is Nothing Then Return Nothing Else Dim result As Integer = data.CompareTo(node.Data) '****** this is the error I get on this line :Object must be of type String.
If result = 0 Then Return node.Data ElseIf result < 0 Then Return Me.Search(data, node.LeftNode) Else Return Me.Search(data, node.RightNode) End If End If
End Function End Class ***************************** The class Person ***************************** Public Class Persoon Inherits BusinessObject Implements IComparable
Private mVnaam As String Private mAnaam As String
Public Sub New(ByVal Vnaam As String, ByVal Anaam As String) Me.mVnaam = Vnaam Me.mAnaam = Anaam End Sub
Public Property Vnaam() As String Get Return Me.mVnaam End Get Set(ByVal value As String) mVnaam = value End Set End Property
Public Property Anaam() As String Get Return Me.mAnaam End Get Set(ByVal value As String) Me.mAnaam = value End Set End Property
Public Overrides Function IsValid() As Boolean If Me.isValidVnaam() And Me.isValidAnaam() Then Return True Else Return False End If End Function
Private Function isValidVnaam() As Boolean If Me.Vnaam.Trim.Length 0 Then Return True Else Return False End If End Function
Private Function isValidAnaam() As Boolean If Me.Anaam.Trim.Length 0 Then Return True Else Return False End If End Function
Public Overloads Function CompareTo(ByVal obj As Object) As Integer Implements System.IComparable.CompareTo Return Me.mVnaam.CompareTo(CType(obj, Persoon).Vnaam) End Function End Class ********************************** The Form : ********************************** Public Class frmBinarySearchTree
Private Sub btnExecute_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExecute.Click Dim bstLedenLijst As New BinarySearchTree Dim bstLidnummer As New BinarySearchTree Dim txtOutput As String = ""
bstLidnummer.Add("5") bstLidnummer.Add("2") bstLidnummer.Add("1") bstLidnummer.Add("4") bstLidnummer.Add("3") txtOutput = bstLidnummer.Search("3") & vbCrLf
bstLedenLijst.Add(New Persoon("Nicole", "Kidman")) bstLedenLijst.Add(New Persoon("Jamie-Lee", "Curtis")) bstLedenLijst.Add(New Persoon("Demi", "Moore")) bstLedenLijst.Add(New Persoon("Julia", "Roberts")) bstLedenLijst.Add(New Persoon("Andie", "MacDowell"))
txtOutput &= bstLedenLijst.Search("Demi") ' & vbCrLf
Me.txtOutput.Text = txtOutput
End Sub
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click Application.Exit() End Sub
End Class This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics
by: jova |
last post by:
Is there a difference between a Binary Tree and a Binary Search Tree? If so
can someone please explain.
Thank You.
|
by: j |
last post by:
Hi,
Anyone out there with binary search tree experience. Working on a
project due tomorrow and really stuck. We need a function that splits
a binary tree into a bigger one and smaller one(for a...
|
by: Tarique Jawed |
last post by:
Alright I needed some help regarding a removal of a binary search
tree. Yes its for a class, and yes I have tried working on it on my
own, so no patronizing please. I have most of the code working,...
|
by: sun6 |
last post by:
this is a program counting words from "text_in.txt" file and writing them in
"text_out.txt". it uses binary tree search, but there is an error when i use
insert ()
thanks for any help
...
|
by: Foodbank |
last post by:
Hi all,
I'm trying to do a binary search and collect some stats from a text
file in order to compare the processing times of this program (binary
searching) versus an old program using linked...
|
by: hn.ft.pris |
last post by:
I have the following code:
Tree.h defines a simple binary search tree node structure
########## FILE Tree.h ################
#ifndef TREE_H
#define TREE_H
//using namespace std;
template...
|
by: whitehatmiracle |
last post by:
Hello
I have written a program for a binary tree. On compiling one has to
first chose option 1 and then delete or search. Im having some trouble
with the balancing function. It seems to be going...
|
by: Defected |
last post by:
Hi,
How i can create a Binary Search Tree with a class ?
thanks
|
by: Vinodh |
last post by:
Started reading about Binary Trees and got the following questions in
mind. Please help.
Definition of a Binary Tree from "Data Structures using C and C++ by
Tanenbaum" goes like this,
"A...
|
by: taylorcarr |
last post by:
A Canon printer is a smart device known for being advanced, efficient, and reliable. It is designed for home, office, and hybrid workspace use and can also be used for a variety of purposes. However,...
|
by: aa123db |
last post by:
Variable and constants
Use var or let for variables and const fror constants.
Var foo ='bar';
Let foo ='bar';const baz ='bar';
Functions
function $name$ ($parameters$) {
}
...
|
by: ryjfgjl |
last post by:
If we have dozens or hundreds of excel to import into the database, if we use the excel import function provided by database editors such as navicat, it will be extremely tedious and time-consuming...
|
by: BarryA |
last post by:
What are the essential steps and strategies outlined in the Data Structures and Algorithms (DSA) roadmap for aspiring data scientists? How can individuals effectively utilize this roadmap to progress...
|
by: nemocccc |
last post by:
hello, everyone, I want to develop a software for my android phone for daily needs, any suggestions?
|
by: Sonnysonu |
last post by:
This is the data of csv file
1 2 3
1 2 3
1 2 3
1 2 3
2 3
2 3
3
the lengths should be different i have to store the data by column-wise with in the specific length.
suppose the i have to...
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can...
|
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers,...
|
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven...
| |