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