#include <algorithm>
#include <iomanip>
#include <ios>
#include <iostream>
#include <string>
#include <vector>

using std::cin;             using std::sort;
using std::cout;            using std::streamsize;
using std::endl;            using std::string;
using std::setprecision;    using std::vector;

int main()
{
	// ask for and read the student's name
	cout << "Please enter your first name: ";
	string name;
	cin >> name;
	cout << "Hello, " << name << "!" << endl;

	// ask for and read the midterm and final grades
	cout << "Please enter your midterm and final exam grades: ";
	double midterm, final;
	cin >> midterm >> final;

	// ask for and read the homework grades
	cout << "Enter all your homework grades, "
	        "followed by end-of-file: ";

	vector<double> homework;
	double x;
	// invariant: `homework' contains all the homework grades read so far
	while (cin >> x)
		homework.push_back(x);

	// check that the student entered some homework grades
	typedef vector<double>::size_type vec_sz;
	vec_sz size = homework.size();
	if (size == 0) {
		cout << endl << "You must enter your grades.  "
		                "Please try again." << endl;	
		return 1;
	}

	// sort the grades
	sort(homework.begin(), homework.end());

	// compute the median homework grade
	vec_sz mid = size/2;
	double median;
	median = size % 2 == 0 ? (homework[mid] + homework[mid-1]) / 2
	                       : homework[mid];

	// compute and write the final grade
	streamsize prec = cout.precision();
	cout << "Your final grade is " << setprecision(3)
	     << 0.2 * midterm + 0.4 * final + 0.4 * median
	     << setprecision(prec) << endl;

	return 0;
}

