3.24

#include<iostream>using namespace std;class date{private:int year;int month;int day;public:int get_year(){return year;}int get_month(){return month;}int get_day(){return day;}void show(){cout<<"the year is:"<<get_year()<<endl;cout<<"the month is:"<<get_month()<<endl;cout<<"the day is:"<<get_day()<<endl;}date(int y,int m,int d);date(const date &d);date(){year=1994;month=02;day=19;}};date::date(int y,int m,int d){year=y;month=m;day=d;}date::date(const date &d){year=2*d.year;month=2*d.month;day=2*d.day;}int main(){date d1(2010,6,8),d2;cout<<"日期d1:"<<endl;d1.show();    cout<<"日期d2:"<<endl;d2.show();   date d3(d1);cout<<"日期d3:"<<endl;d3.show();return 0;}