12.3派生类 时间日期

#include <iostream>using namespace std;class Date{public:    Date(int y,int m,int d):Year(y),Month(m),Day(d) {}    void SetDate(int y,int m,int d);    void PrintDate();protected:    int Year;    int Month;    int Day;};class Time{public:    Time(int h,int m,int s):Hour(h),Minute(m),Second(s) {}    void SetTime(int h,int m,int s);    void PrintTime();protected:    int Hour;    int Minute;    int Second;};class DateTime:public Date,public Time{public:    DateTime(int year=0,int month=0,int day=0,int hour=0,int minute=0,int second=0):Date(year,month,day),Time(hour,minute,second) {}    void PrintDate_Time();};void Date::SetDate(int y,int m,int d){    Year=y;    Month=m;    Day=d;}void Date::PrintDate(){    cout<<"当前日期为："<<Year<<"年 "<<Month<<"月 "<<Day<<"日"<<endl;}void Time::SetTime(int h,int m,int s){    Hour=h;    Minute=m;    Second=s;}void Time::PrintTime(){    cout<<"当前时间为："<<Hour<<"时 "<<Minute<<"分 "<<Second<<"秒"<<endl;}void DateTime::PrintDate_Time(){    PrintDate();    PrintTime();}int main(){    DateTime dt_a,dt_b(2010,4,16,9,30,0);    cout<<"dt_a: ";    dt_a.PrintDate_Time();    cout<<endl;    cout<<"dt_b: ";    dt_b.PrintDate_Time();    dt_a.SetTime(20,00,00);    dt_a.SetDate(2008,8,7);    cout<<endl;    cout<<"dt_after uptate: ";    dt_a.PrintDate_Time();    return 0;}