C++11 homework example (Superbowl scores)

superbowl.cpp

#include <iostream>
#include <fstream>
#include <iomanip>
#include <vector>
#include <string>
#include <limits>
#include <iterator>
#include <algorithm>
#include <utility>
using namespace std;

class GameList {
    struct Game {
        string winner, loser;
        int score;
        bool operator<(const Game& rhs) { return score < rhs.score; }
        friend istream& operator>>(istream& is, Game& g) {
            getline(is, g.winner);
            getline(is, g.loser);
            is >> g.score;
            return is.ignore(numeric_limits<streamsize>::max(), '\n'); 
        }
        friend ostream& operator<<(ostream& os, const Game& g) {
            return os << left << setw(15) << g.winner << setw(15) << g.loser << g.score << '\n';
        }
    };
    vector<Game> games;
  public:
    GameList(istream& is) : games { istream_iterator<Game>(is), istream_iterator<Game>() } {}
    friend ostream& operator<<(ostream& os, const GameList& gl) {
        os << left << setw(15) << "Winner" << setw(15) << "Loser" << "Score\n";
        copy(begin(gl.games), end(gl.games), ostream_iterator<Game>(os));
        return os << '\n';
    }
    double average_score() {
        return accumulate(begin(games), end(games), 0.,
            [](double t, const Game& g) { return t + g.score; }) / games.size();
    }
    size_t win_more_than(int thresh) {
        return count_if(begin(games), end(games), [=](const Game& g) { return g.score > thresh; });
    }
    pair<string, string> most_pts() {
        const Game &g = *max_element(begin(games), end(games));
        return { g.winner, g.loser };
    }
    pair<string, string> fewest_pts() {
        const Game &g = *min_element(begin(games), end(games));
        return { g.winner, g.loser };
    }  
};

int main()
{
    ifstream infile { "superbowl.dat" };
    if(!infile) {
        cout << "Can't read file.\n";
        return 1;
    }
    GameList gl { infile };
    cout << gl;
    cout << "Average number of points scored by winning teams: " << gl.average_score() << "\n";
    cout << "Number of winning teams that scored more than 40: " << gl.win_more_than(40) << "\n";
    string w, l;
    tie(w, l) = gl.most_pts();
    cout << "Winner of game with most points scored was " << w << " and loser was " << l << "\n";
    tie(w, l) = gl.fewest_pts();
    cout << "Winner of game with fewest points scored was " << w << " and loser was " << l << "\n";
}

superbowl.cpp-output.txt

Winner         Loser          Score
Packers        Chiefs         35
Packers        Raiders        33
Jets           Colts          16
Chiefs         Vikings        23
Colts          Cowboys        16
Cowboys        Dolphins       24
Dolphins       Redskins       14
Dolphins       Vikings        24
Steelers       Vikings        16
Steelers       Cowboys        21
Raiders        Vikings        32
Cowboys        Broncos        27
Steelers       Vikings        35
Steelers       Rams           31
Raiders        Eagles         27
49ers          Bengals        26
Redskins       Dolphins       27
Raiders        Redskings      38
49ers          Dolphins       38
Bears          Patriots       46
Giants         Broncos        39
Redskins       Broncos        42
49ers          Bengals        20
49ers          Broncos        55
Giants         Bills          20
Redskins       Bills          37
Cowboys        Bills          52
Cowboys        Bills          30
49ers          Chargers       49
Cowboys        Steelers       27
Packers        Patriots       35
Broncos        Packers        31
Broncos        Falcons        34
Rams           Titans         23
Ravens         Giants         34
Patriots       Rams           20
Buccaneers     Raiders        48
Patriots       Panthers       32
Patriots       Eagles         24
Steelers       Seahawks       21
Colts          Bears          29
Giants         Patriots       17
Steelers       Cardinals      27
Saints         Colts          31
Packers        Steelers       31
Giants         Patriots       21
Ravens         49ers          34

Average number of points scored by winning teams: 30.0426
Number of winning teams that scored more than 40: 6
Winner of game with most points scored was 49ers and loser was Broncos
Winner of game with fewest points scored was Dolphins and loser was Redskins

superbowl.dat

Packers
Chiefs
35
Packers
Raiders
33
Jets
Colts
16
Chiefs
Vikings
23
Colts
Cowboys
16
Cowboys
Dolphins
24
Dolphins
Redskins
14
Dolphins
Vikings
24
Steelers
Vikings
16
Steelers
Cowboys
21
Raiders
Vikings
32
Cowboys
Broncos
27
Steelers
Vikings
35
Steelers
Rams
31
Raiders
Eagles
27
49ers
Bengals
26
Redskins
Dolphins
27
Raiders
Redskings
38
49ers
Dolphins
38
Bears
Patriots
46
Giants
Broncos
39
Redskins
Broncos
42
49ers
Bengals
20
49ers
Broncos
55
Giants
Bills
20
Redskins
Bills
37
Cowboys
Bills
52
Cowboys
Bills
30
49ers
Chargers
49
Cowboys
Steelers
27
Packers
Patriots
35
Broncos
Packers
31
Broncos
Falcons
34
Rams
Titans
23
Ravens
Giants
34
Patriots
Rams
20
Buccaneers
Raiders
48
Patriots
Panthers
32
Patriots
Eagles
24
Steelers
Seahawks
21
Colts
Bears
29
Giants
Patriots
17
Steelers
Cardinals
27
Saints
Colts
31
Packers
Steelers
31
Giants
Patriots
21
Ravens
49ers
34