OJ 1.P

/*Description设计一个日期类和时间类，编写display函数用于显示日期和时间。要求：将Time类声明为Date类的友元类，通过Time类中的display函数引用Date类对象的私有数据，输出年、月、日和时、分、秒。Input年、月、日和时、分、秒Output年、月、日和时、分、秒*/#include <iostream>using namespace std;class Time;class Date{    public:    friend class Time;    Date(int a,int b,int c):year(a),month(b),day(c){}    private:    int year;    int month;    int day;};class Time{    public:    Time(int h,double m,double s):hour(h),minute(m),sec(s){}    void display(const Date &d);    private:    int hour;    double minute;    double sec;};void Time::display(const Date &d){    cout<<d.year<<"/"<<d.month<<"/"<<d.day<<endl;    cout<<hour<<":"<<minute<<":"<<sec<<endl;}int main(){    int year,month,day;    cin>>year>>month>>day;    Date d1(year,month,day);    int hour,minute,second;    cin>>hour>>minute>>second;    Time t1(hour,minute,second);    t1.display(d1);    return 0;}