static void fillInDayOfYear(byte[] mon, byte[] days, int[] daysInMon) { int m = 0, d = 1; for (int i=0; i<mon.Length; ++i) { mon[i] = (byte)m; days[i] = (byte)(d++); if (d > daysInMon[m]) { m++; d = 1; } } }