2.CTime

CTime中默认的构造函数不初始化成员，所以这样创建的对象，就这样使用会出问题一般不这样用

GetDayOfWeek()要注意返回值1 = Sunday, 2 = Monday, to 7 = Saturday

计算两个日期相差时间可以直接相减

CTime t1,t1

CTimeSpan ts=t1-t2

ts两个日期相差的一个时间类-2.CTime CTime default constructor does not initialize the members, so this creates an object, and thus generally do not like to use there might be problems with the GetDayOfWeek () should pay attention to returns the value 1 = Sunday, 2 = Monday, to 7 = Saturday calculate the time difference between two dates can be directly subtract CTime t1, t1　CTimeSpan ts = t1-t2　ts of a time difference between two dates, class