iOS根据当前时间的计算前/后 几年几个月几日的时间

• (NSDate *)getLaterDateFromDate:(NSDate *)date withYear:(NSInteger)year month:(NSInteger)month day:(NSInteger)day {
  NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
  NSDateComponents *comps = nil;
  comps = [calendar components:NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:date];
  NSDateComponents *adcomps = [[NSDateComponents alloc] init];
  [adcomps setYear:year];
  [adcomps setMonth:month];
  [adcomps setDay:day];
  NSDate *newdate = [calendar dateByAddingComponents:adcomps toDate:date options:0];
  return newdate;
  }