第3题

#include using namespace std;class Date{public:Date(int=1,int=1,int=2005);void display();private:int month;int day;int year;};Date::Date(int m,int d,int y):month(m),day(d),year(y){}void Date::display(){ cout<<month<<":"<<day<<":"<<year<<endl;}int main(){ Date d1(10,13,2005); Date d2(12,30); Date d3(10); Date d4; d1.display(); d2.display(); d3.display(); d4.display(); return 0;}