#include <iostream>
#include <vector>
#include <string>
#include <cstdlib>
#include <fstream>
#include <sstream>
#include <iomanip>
using namespace  std;

void readFile(string filename, vector<double> &finals);
double average(const vector<double> &finals);
double median(vector<double> finals);
void display(const vector<double> &finals, double avg, double median);
int main()
{
string filename;
vector<double> final_scores;
double avg, med;
cout << "Enter input filename: ";
cin >> filename;
readFile(filename, final_scores);
avg = average(final_scores);
med = median(final_scores);
display(final_scores, avg, med);
}

void readFile(string filename, vector<double> &finals)
{
ifstream infile(filename.c_str());
if(infile.fail())
{
cout << "ERROR: could not open input file " << filename << endl;
exit(1);
}
string line;
double avg, score;
int n;
while(getline(infile, line)) //get the line of scores for a student
{
avg = 0;
n = 0;
stringstream lstream(line);
while(lstream >> score) //calculate average of scores for a single student and push the average into finals
{
avg += score;
n++;
}
avg /= n;
finals.push_back(avg);
}
infile.close();
}
double average(const vector<double> &finals)
{
double avg = 0;
for(int i = 0; i < finals.size(); i++)
avg += finals[i];
avg /= finals.size();
return avg;
}
double median(vector<double> finals)
{
double median;
int mid = finals.size() / 2;
sort(finals.begin(), finals.end());
if(finals.size() % 2 == 1) //odd length
median = finals[mid];
else
median = (finals[mid] + finals[mid-1])/2; //average of middle 2 values
return median;
}
void display(const vector<double> &finals, double avg, double median)
{
cout << "The scores for the students is" << endl;
cout << fixed << setprecision(2);
for(int i =0; i < finals.size(); i++)
{
cout << (i+1) << ". " << finals[i] << endl;
}
cout << endl << "The average score is " << avg << endl;
cout << "The median score is " << median << endl;
}