I really need help with a vb question....

I'm a newbie in programming so I'm kinda confused on how to do this:

msg me asap:[email protected](msn messenger) I am online as we speak.

it says:

Create a program with one textbox called txtnum and a listbox called lstresult. the textbox will be used to capture a positive integer greater than zero and after a button called btncacfactorial is clicked, the list box will be used to display that number's factorial. For example, if the user entered 3 in the textbox and then clicked the button, 6 (which is 3*2*1)shoudl be displayed in the lsitbox. Be sure to clear the listbox before you output the factorial for each number entered. ALso, bullet proof your program to allow only positive integers greater than zero; if the user does not enter a valid entry, give the user an appropriate message box.

I really need help on this. I have made the layouts with the textbox and listbos and the command button, but i desperately am lost on the coding, please help me.

I really need a response on this within the next few hours the latest. Thank you.

Can you post what you've tried so far? If you have a specific problem, I'm sure you'll get some help.

factorial function

VB Code:

Function factorial(ByVal number As Integer) As Long
        If number > 0 Then
            factorial = number * factorial(number - 1)
        ElseIf number = 0 Then
            Return 1
        End If
    End Function

VB Code:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
      ListBox1.Items.Clear()  ' clearing
      Dim n As Integer
      Try
         n = Integer.Parse(TextBox1.Text)
      Catch ex As Exception
         MessageBox.Show("casting exception")
         Exit Sub
      End Try
      If n < 1 Then
         MessageBox.Show("bullet proof")   '  bullet proof
      End If
      '  i assume you put the result to last item of the listbox
      ListBox1.Items.Add(factorial(n))
   End Sub
 
   Function factorial(ByVal n As Integer) As Integer
      If n > 0 Then
         factorial = n * factorial(n - 1)
         ListBox1.Items.Add(n)
      ElseIf n = 0 Then
         Return 1
      End If
   End Function

next time mate, could you post even a little code. we just assume about this one.