ostream& operator<<(ostream& ost, const date &d)
{
	ost << d.month << "/" << d.day << "/" << d.year;
	return ost;
}

istream& operator>>(istream& ist, date& d)
{
	int month;      //uninitialized variable
	ist >> month;
	if (!ist) {     //if (ist.operator!()) {
		return ist;
	}

	char c;         //uninitialized variable
	ist >> c;
	if (!ist) {
		return ist;
	}
	if (c != '/') {
		ist.setstate(ios_base::failbit);
		return ist;
	}

	int day;        //uninitialized variable
	ist >> day;
	if (!ist) {
		return ist;
	}

	ist >> c;
	if (!ist) {
		return ist;
	}
	if (c != '/') {
		ist.setstate(ios_base::failbit);
		return ist;
	}

	int year;       //uninitialized variable
	ist >> year;
	if (!ist) {
		return ist;
	}

	//Put no values into d until we've verified that all three are valid.

	if (month < date::january || month > date::december) {
		cerr << "bad month " << month << "\n";
		ist.setstate(ios_base::failbit);
		return ist;
	}

	if (day < 1 || day > date::length[month]) {
		cerr << "bad day " << day << " of month " << month << "\n";
		ist.setstate(ios_base::failbit);
		return ist;
	}

	d.year = year;
	d.month = month;
	d.day = day;

	return ist;     //as in the above line 4
}