p 305 类外的友元函数.cpp

谭浩强 《C++ 程序设计》第三版的部分课后练习题源码

#include<iostream>
using namespace std;
class Date;
class Time
    {  
       private:
               int hour;
               int minute;
               int second;
       
       public:
              Time(int a,int b,int c):hour(a),minute(b),second(c){} 
              friend void display(Date &d,Time &t);
          
    };
    
    class Date
{
      private:
              int date;
              int month;
              int year;
              
      public:
             Date(int a,int b,int c):month(a),date(b),year(c){}
             friend void display(Date &d,Time &t);
             
};


void display(Date &d,Time &t)
{
     cout<<d.month<<"/"<<d.date<<"/"<<d.year<<endl;
     cout<<t.hour<<": "<<t.minute<<": "<<t.second<<endl;    
     
}


int main()
{
    Date d(12,25,2004);
    Time t(10,23,45);
    display(d,t);
    system("pause");
    return 0;
}