如果只有開始跟結束的小時，要如何判斷是今日或昨日

NSCalendar *cal = [NSCalendar currentCalendar];

            NSDateComponents *sleepComps = [cal components:NSHourCalendarUnit | NSMinuteCalendarUnit fromDate:se.sleepDate];

            NSDateComponents *wakeUpComps = [cal components:NSHourCalendarUnit | NSMinuteCalendarUnit fromDate:se.wakeUpDate];

            date = [_displayDate startDayDate];

            if (sleepComps.hour > wakeUpComps.hour)

                date = [date dateByAddingTimeInterval:-86400];