struct Student
{
    char fullName[N];
    int course;
    int group;
};

bool operator < (Student& student1, Student &student2)
{
    return student1.group < student2.group;
}

// /*
void addRecordToBack()
{
    Student student;
    int n = 0;
    cout << "Введите кол-во новых записей: "; cin >> n;
    fstream file("student.bin", ios::binary | ios::out | ios::app);
    cin.clear();
    while (cin.get() != '\n');
    for (int i = 0; i < n; i++)
    {
        while (cin.get() != '\n');
        cin.clear();
        cout << "фио "; cin.getline(student.fullName, N, '\n');
        cout << "курс: "; cin >> student.course;
        cout << "группа "; cin >> student.group;
        file.write(reinterpret_cast<char*>(&student), sizeof(student));

    }
    file.close();
}
//*/

int numberOfRecords()
{
    Student item;
    ifstream file;
    file.open("student.bin");
    file.seekg(0, ios::end);
    int result = file.tellg() / sizeof(item);
    file.close();
    return result;
}

vector<Student> getAllRecordsFromFile()
{
    int countOfRecords = numberOfRecords();
    vector<Student> arrayOfRecords(countOfRecords);
    fstream file("student.bin", ios::binary | ios::in);
    for (int i = 0; i < countOfRecords; i++)
        file.read(reinterpret_cast<char*>(&arrayOfRecords[i]), sizeof(arrayOfRecords[i]));
    file.close();
    return arrayOfRecords;
}

int main()
{
    vector<Student> students = getAllRecordsFromFile();
    setlocale(0, "");
    sort(students.begin(), students.end());
    for (int i = 0; i < students.size(); i++)
    {
        cout << "фио " << students[i].fullName;
        cout << "\nкурс: " << students[i].course;
        cout << "\nгруппа " << students[i].group;
        cout << endl;
    }
    fstream file("student1.bin", ios::binary | ios::out);
    file.close();
    file.open("student1.bin", ios::binary | ios::out);
    for (int i = 0; i < students.size(); i++)
        file.write(reinterpret_cast<char*>(&students[i]), sizeof(students[i]));
    file.close();
    return 0;
}