a stack using a linked list

Using a Linked List, a Stack is implemented by adding NEW entries to the Head of the List, and removing entries from the HEAD of the list.  as you add new items, the Hewad pointer points to the new item, and the new item's pointer points to the previous Head of List item.

does that give you enough to start with?

AW

oops, typo:


...the Hewad pointer points ... should read ...the Head pointer points ....

so you will have a variable to hold the 'pointer' to the head of the list.

AW

How do I write code for pointers in VB.  This is new to me.  I am just learning about stacks.

Before we go into detail, is this homework? If so, we can't provide full code, but we will do what we can to help you.
Also, you don't use pointers directly VB really.  I think Arthur_Wood meant pointers as in general theory.

You'll need to design a class that represents the "stack" which is basically a collection of "elements" and give it functions to
-Add an Element (push) - this will add the specified element to the stack, and move the stack "pointer" to the top of the stack
-Get an Element (pop) - this will give back the element at the top of the stack, and move the stack "pointer" down one element.

If you imagine it like a tall box, into which you are putting plates and taking them out, it should be easy to visualise in terms of how to "push" and "pop" items.

Let us know if you need more help.

Not looking for the code,  just some directions as I had no idea how to begin.

Thank you

Here is how to do it using a LinkedList implementation that can handle either primitives or objects.  Both uses are shown in the demonstration app below:

' --------------------------------------------------
' Class StackNode
' --------------------------------------------------
Option Explicit

Public Item As Variant
Public NextNode As StackNode

' --------------------------------------------------
' Class Stack
' --------------------------------------------------
Option Explicit

Private HeadNode As StackNode
Private StackCount As Integer

Public Property Get Count() As Integer
    Count = StackCount
End Property

Public Sub Push(ByRef Item As Variant)
    On Error Resume Next ' handle both objects and primitives
   
    Dim newNode As New StackNode
   
    Set newNode.Item = Item
    newNode.Item = Item
   
    Set newNode.NextNode = HeadNode
    Set HeadNode = newNode
   
    StackCount = StackCount + 1
End Sub

Public Function Pop() As Variant
    If Not (HeadNode Is Nothing) Then
        On Error Resume Next ' handle both objects and primitives
       
        Pop = HeadNode.Item
        Set Pop = HeadNode.Item
       
        Set HeadNode = HeadNode.NextNode
       
        StackCount = StackCount - 1
    Else
        MsgBox "Nothing to Pop!", vbCritical, "Empty Stack"
    End If
End Function

' --------------------------------------------------
' Form1
' --------------------------------------------------
Option Explicit

Private Sub Command1_Click()
    ' demonstrate the stack working with a primitive (Integer)
    Dim i As Integer
    Dim s As New Stack
   
    Debug.Print "Pushing:"
    For i = 1 To 5
        s.Push i
        Debug.Print i
    Next i
   
    Debug.Print "Popping:"
    While s.Count > 0
        Debug.Print s.Pop
    Wend
End Sub

Private Sub Command2_Click()
    ' demonstrate the stack working with an object (StackNode)
    Dim i As Integer
    Dim s As New Stack
    Dim sn As StackNode
   
    Debug.Print "Pushing:"
    For i = 1 To 5
        Set sn = New StackNode
        sn.Item = i
        s.Push sn
        Debug.Print sn.Item
    Next i
   
    Debug.Print "Popping:"
    While s.Count > 0
        Set sn = s.Pop
        Debug.Print sn.Item
    Wend
End Sub