#ifndef DATE0_H
#define DATE0_H
#include <iostream>
using namespace std;

class date0 {
	virtual void print(ostream& ost) const;
public:
	date0(int initial_month, int initial_day, int initial_year);
	virtual ~date0() {}

	static const int length[];   //no non-static data members

	virtual date0& operator+=(int count);
	virtual date0& operator++();

	friend ostream& operator<<(ostream& ost, const date0& d) {
		d.print(ost);
		return ost;
	}
};

#endif