c9-12.cpp

这我们老师对是面向对象程序设计（清华大学出版社）一书制作的PPT

#include <iostream>
using namespace std;

class Time
 {public:
   Time(int,int,int);
   friend void display(Time &);
  private:
   int hour;
   int minute;
   int sec;
 };
 Time::Time(int h,int m,int s)
 {hour=h;
  minute=m;
  sec=s;
 }
void display(Time &t)
 {
  cout<<t.hour<<":"<<t.minute<<":"<<t.sec<<endl;
 }
   
int main()
{
 Time t1(10,13,56);
 display(t1);
 return 0;
}