Помогите пожалуйста, не могу понять как сделать С++

#include <iostream>
#include <vector>
#include <string>
#include <iterator>
#include <iomanip>
using namespace std;
struct Player {
string name;
unsigned age;
unsigned quantity;
unsigned scored;
friend ostream& operator<<(ostream& out, const Player& player) {
out
<< setw(25U) << left << player.name << right
<< setw(5U) << player.age
<< setw(6U) << player.quantity
<< setw(5U) << player.scored;
return out;
}
};
int main() {
vector<Player> players{
{ "Telegin Ivan"s, 29U, 38U, 9U },
{ "Ovechkin Alexander"s, 33U, 106U, 45U },
{ "Malkin Evgeny"s, 32U, 83U, 39U },
{ "Andronov Sergei"s, 29U, 33U, 5U },
{ "Anisimov Artyom"s, 31U, 64U, 10U },
{ "Plotnikov Sergei"s, 29U, 40U, 11U },
{ "Grigorenko Mikhail"s, 25U, 24U, 9U },
{ "Dadonov Evgenii"s, 30U, 62U, 22U },
{ "Kovalchuk Ilia"s, 36U, 127U, 51U },
{ "Kaprizov Kirill"s, 22U, 23U, 13U },
{ "Kucherov Nikita"s, 25U, 24U, 15U },
{ "Kuznetsov Evgenii"s, 27U, 48U, 10U },
{ "Barabanov Alexander"s, 24U, 32U, 4U },
{ "Gusev Mikhail"s, 26, 29U, 16U }
};
copy(players.begin(), players.end(), ostream_iterator<Player>(cout, "\n"));
cout.put('\n');
cout << "Age: ";
unsigned age;
cin >> age;
cout.put('\n');
for (const auto player : players) if (player.age < age) cout << player << '\n';
cout.put('\n');
system("pause");
}

https://pastebin.com/ZbYbJV7T

#include <iostream>
#include <string>
#include <vector>

using namespace std;

struct HockeyPlayer {
   string surname;
   int age;
   int numberOfGames;
   int numberOfGoals;
};

HockeyPlayer input();
void display(HockeyPlayer);

int main() {
   vector<HockeyPlayer> players;
   int numberOfPlayers;

   cout << "Enter number of players: ";
   cin >> numberOfPlayers;
   for(int i = 0; i < numberOfPlayers; ++i) {
     HockeyPlayer player = input();
     players.push_back(player);
   }

   double averageAge = 0;
   for(auto p: players) {
     averageAge += p.age;
   }
   averageAge /= players.size();
   cout << "Average age of hockey players: " << averageAge << endl;

   for(auto p: players) {
     if (p.age < 25) {
       display(p);
     }
   }
   return 0;
}

HockeyPlayer input() {
   HockeyPlayer player;
   cout << "Enter a hockey player's data:\n";
   cout << "Surname: ";
   cin >> player.surname;
   cout << "Age: ";
   cin >> player.age;
   cout << "Number of games: ";
   cin >> player.numberOfGames;
   cout << "Number of goals: ";
   cin >> player.numberOfGoals;
   return player;
}

void display(HockeyPlayer player) {
   cout << "Player:\n";
   cout << "Surname: " << player.surname << endl;
   cout << "Age: " << player.age << endl;
   cout << "Number of games: " << player.numberOfGames << endl;
   cout << "Number of goals: " << player.numberOfGoals << endl;
}