I wish to use this function to calculate the difference in days between two dates - and know the syntax for the formula and how to make it "run" on a change on the worksheet.

My dilemas are:
1. How to define the function to use a "call" in the macro.
2. how to "name/label/define" my dates
3. How to put the result of the function in the cell immediately to the left after the calculation is done

Any suggestions/help?

Private Sub Worksheet_Change(ByVal Target As Range)
Dim TheDate As Range
Dim cell As Range
Dim lastrow As Long
Dim startrow As Long
Dim col As Long
Dim daysoos As Integer

startrow = 3
col = 2

lastrow = findLastRow(col)
daysoos = diffdate()
Set TheDate = Range(Cells(startrow, col), Cells(lastrow, col))



For Each cell In TheDate

If cell > 0 Then
daysoos.End(xlUp).Offset (cell(0, -1))

Else
'Don't worry be happy!!!!!


End If
Next cell