VBA : Implement a Tree structure

[kimpro82]

By ChatGPT

• Define TreeNode Class

  ' Define a node in the tree structure.
  Class TreeNode
    Public Value As Variant
    Public Children As Collection
  
    ' Constructor to initialize the node.
    Public Sub Initialize()
        Set Children = New Collection
    End Sub
  End Class

[kimpro82]

By ChatGPT

• Add Tree class to manage the tree structure

  ' Define a class to manage the tree structure.
  Class Tree
    Public Root As TreeNode
  
    ' Method to insert a node with a specific value as a child of a parent node.
    Public Sub Insert(parentValue As Variant, newValue As Variant)
        Dim newNode As New TreeNode
        newNode.Value = newValue
  
        If Root Is Nothing Then
            ' The tree is empty. Create the root node.
            Set Root = newNode
        Else
            ' Search for the parent node.
            Dim parentNode As TreeNode
            Set parentNode = SearchNode(Root, parentValue)
  
            If Not parentNode Is Nothing Then
                ' Add the new node as a child of the parent node.
                parentNode.Children.Add newNode
            Else
                ' Parent node not found.
                Debug.Print "Parent node with value " & parentValue & " not found."
            End If
        End If
    End Sub
  
    ' Method to search for a node with a specific value.
    Private Function SearchNode(startNode As TreeNode, searchValue As Variant) As TreeNode
        Dim currentNode As TreeNode
        If startNode.Value = searchValue Then
            ' Node found.
            Set SearchNode = startNode
            Exit Function
        Else
            ' Recursively search among the children.
            For Each currentNode In startNode.Children
                Set SearchNode = SearchNode(currentNode, searchValue)
                If Not SearchNode Is Nothing Then Exit Function
            Next currentNode
        End If
  
        ' Node not found.
        Set SearchNode = Nothing
    End Function
  
    ' Method to display the tree structure.
    Public Sub Display()
        DisplayNode Root, 0
    End Sub
  
    ' Recursive method to display a node and its children.
    Private Sub DisplayNode(node As TreeNode, level As Integer)
        Dim i As Integer
        For i = 1 To level
            Debug.Print "  ";
        Next i
        Debug.Print node.Value
        For Each childNode In node.Children
            DisplayNode childNode, level + 1
        Next childNode
    End Sub
  End Class

[kimpro82]

By ChatGPT

• Test

  Sub TestTreeOperations()
    ' Create a tree and insert nodes.
    Dim myTree As New Tree
    myTree.Insert "Root", "Child1"
    myTree.Insert "Root", "Child2"
    myTree.Insert "Child1", "Grandchild1"
    myTree.Insert "Child1", "Grandchild2"
    myTree.Insert "Child2", "Grandchild3"
  
    ' Display the initial tree structure.
    Debug.Print "Initial Tree Structure:"
    myTree.Display
    Debug.Print "------------------------"
  
    ' Traverse the tree (Depth-First Search).
    Debug.Print "Depth-First Search:"
    TraverseDF myTree.Root
    Debug.Print "------------------------"
  
    ' Delete a node.
    myTree.Delete "Child1"
  
    ' Display the updated tree structure.
    Debug.Print "Tree Structure after Deleting 'Child1':"
    myTree.Display
    Debug.Print "------------------------"
  End Sub
  
  ' Method to traverse the tree using Depth-First Search.
  Sub TraverseDF(startNode As TreeNode)
    Debug.Print startNode.Value
    Dim childNode As Variant
    For Each childNode In startNode.Children
        TraverseDF childNode
    Next childNode
  End Sub