第三章第十题

#include <iostream>using namespace std;class Date;class Time {public:   Time(int,int,int);   friend void display(const Date &,const Time &);  private:   int hour;   int minute;   int sec; }; Time::Time(int h,int m,int s) {hour=h;  minute=m;  sec=s; }class Date {public:Date(int,int,int);   friend void display(const Date &,const Time &);  private:   int month;   int day;   int year; };Date::Date(int m,int d,int y) {month=m;  day=d;  year=y; }void display(const Date &d,const Time &t) {  cout<<d.month<<"/"<<d.day<<"/"<<d.year<<endl;  cout<<t.hour<<":"<<t.minute<<":"<<t.sec<<endl; }int main(){ Time t1(10,13,56); Date d1(12,25,2004); display(d1,t1); return 0;}