// compute a student's overall grade from midterm and final exam grades
// and vector of homework grades.
// this function does not copy its argument, because `median' does so for us.
double grade(double midterm, double final, const vector<double>& hw)
{
	if (hw.size() == 0)
		throw domain_error("student has done no homework");
	return grade(midterm, final, median(hw));
}

