试题八(15分,每空3分) [说明] 下面程序的功能是计算并输出某年某月的天数。 [C++程序] #include < iostream> using namespace std; ___(1)___ Month ( Jan , Feb , Mar , Apr , May , Jun , Jul , Aug , Sep , Oct , Nov , Dec ) ; class Date { public: Date ( int year , Month m_month ) { ___(2)___ = year ; if ( m_month < Jan || m_month > Dec ) month = Jan; else month = m_month; } ; ~Date () {} ; bool IsLeapYear () { return ( ( year % 4 = = 0&&year % 100 != 0 ) || year %400 = = 0); }; int CaculateDays () { switch ( ___(3)___ ) { case Feb : { if ( ___(4)___ ) return 29; else return 28; } case Jan : case Mar : case May : case Jul : case Aug : case : Oct: case Dec : return 31; case Apr : case Jun : case Sep : case Nov : return 30; } }; private : int year; Month month; }; Void main () { Date day ( 2000 ,Feb ); Cout << day. ___(5)___ (); }