Macro to compare cell values

[Zimmerman]

Does anybody know how to create a macro that will loop through the active sheet and compare the cell values in Cells O8:O37 against cells P8:P37? If the cell value in cells o837 are lower than the P8:P37 then a warning will pop up stating which cells are lower.
Thanks
Windows XP
Excel 2003

 

[mikerickson]

Dim i As Long
Dim warningString As String

For i = 8 to 37
    With .Cells(i,15)
        If Val(CStr(.Value)) < Val(CStr(.Offset(0, 1).Value)) Then
            warningString = warningString & ", " & .Address
        End If
    End With
Next i

warningString = Mid(warningString, 3)

If warningString <> vbNullString Then
    MsgBox "Cells " & warningString & " are lower than their counterparts"
End If