static void refillComboBox (QComboBox *combo, const QString items[], int number_of_items, int selected_item);
#define ITEMS(x) sizeof x / sizeof x[0] static const QString foo[] = { "Hz", "kHz" }; refillComboBox(ui.comboBlaBlaBla, foo, ITEMS(foo), 0 }; static const QString bar[] = { micro + "s", "ms", "s" }; refillComboBox(ui.comboBlaBlaBla, bar, ITEMS(bar), 3 };