在C#中,给出一组任意的DayOfWeek终点(如DayOfWeek.Friday和DayOfWeek.Sunday),如果一个任意日期是在两天之间,包含在内的怎么样呢？
例：
- // result == true; Oct 23,2010 is a Saturday
- var result = InBetweenDaysInclusive(new DateTime(2010,10,23),DayOfWeek.Friday,DayOfWeek.Sunday);
- // result == true; Oct 22,2010 is a Friday
- result = InBetweenDaysInclusive(new DateTime(2010,22),DayOfWeek.Sunday);
- // result == true; Oct 24,2010 is a Sunday
- result = InBetweenDaysInclusive(new DateTime(2010,24),DayOfWeek.Sunday);
- // result == false; Oct 25,2010 is a Monday
- result = InBetweenDaysInclusive(new DateTime(2010,25),DayOfWeek.Sunday);
谢谢！
解决方法
根据开始和结束日期之间的差异是负数还是正/零,此函数将需要两个独立的分支.
我可以完全脱离基地,但我认为这适用于所有情况：
- // No state in method,so made it static
- public static bool InBetweenDaysInclusive(DateTime date,DayOfWeek start,DayOfWeek end)
- {
- DayOfWeek curDay = date.DayOfWeek;
- if (start <= end)
- {
- // Test one range: start to end
- return (start <= curDay && curDay <= end);
- }
- else
- {
- // Test two ranges: start to 6,0 to end
- return (start <= curDay || curDay <= end);
- }
- }
作为参考,当我运行它时,您的测试数据返回以下内容,并为每个结果添加了Console.WriteLine：
- True
- True
- True
- False
编辑：我最后的解释太模糊了.这是一个固定的.
诀窍在于,开始,那么你有两个有效的范围：开始上限和下限结束.这将导致(开始< = curDay&& curDay< = upperBound)|| curDay< = end&&& lowerBound< = curDay) 然而,由于它们是边界,所以curDay总是< = upperBound和> = lowerBound,因此我们省略了该代码.
