12周 项目4

#include 
  
   
using namespace std;
class Date
{
public:
    Date(int y=0,int m=0,int d=0);
    void SetDate(int y,int m,int d);
    void PrintDate();
protected:
    int year;
    int month;
    int day;
};
Date::Date(int y,int m,int d):year(y),month(m),day(d) {}
void Date::SetDate(int y,int m,int d)
{
    year=y;
    month=m;
    day=d;
}
void Date::PrintDate()
{
    cout<