Sub Macro9()
Dim derlig, t, i&
With Sheets("Feuil1")
If .FilterMode Then .ShowAllData
derlig = .Cells(.Rows.Count, "a").End(xlUp).Row
t = .Range("a1:c" & derlig)
For i = 2 To UBound(t)
If t(i, 1) <> "" Then t(i, 3) = "ok"
Next i
.Range("c1:c" & derlig) = Application.Index(t, 0, 3)
End With
End Sub