Making rows invisible with VBA

try this (given the values in A are determined by a formula and the macro is kicked off manually)

Sub HideShowZeroRows()
Dim cl As Range
For Each cl In Range("A18:A49")
    If cl.Value = 0 Then
        Rows(cl.Row).EntireRow.Hidden = True
    Else
        Rows(cl.Row).EntireRow.Hidden = False
    End If
Next cl
End Sub