C++ solved inheritance problem from hackerrank

C++ solved inheritance problem from hackerrank:

#include <iostream>
#include <vector>

using namespace std;


class Person{
    protected:
        string firstName;
        string lastName;
        int id;
    public:
        Person(string firstName, string lastName, int identification){
            this->firstName = firstName;
            this->lastName = lastName;
            this->id = identification;
        }
        void printPerson(){
            cout<< "Name: "<< lastName << ", "<< firstName <<"\nID: "<< id << "\n";
        }
   
};

class Student :  public Person{
    private:
        vector<int> testScores; 
    public:
          // Write your constructor
        Student(string firstName, string lastName, int identification, vector<int> scores): Person(firstName, lastName, identification), testScores(scores) {
        }
          // Write char calculate()
        char calculate() {
            int sum = 0;
            int count = 0;
            vector<int>::iterator it;
            for(it = testScores.begin(); it != testScores.end(); ++it) {
                sum+= *it;
                count++;
            }
            int avg = sum/count;
            if (90 <= avg && avg <=100)
                return 'O';
            else if(80<= avg && avg < 90)
                return 'E';
            else if(70<= avg && avg < 80)
                return 'A';
            else if(55<= avg && avg < 70)
                return 'P';
            else if(40 <= avg && avg < 55)
                return 'D';
             else
                return 'T';
        }
};

int main() {
    string firstName;
      string lastName;
    int id;
      int numScores;
    cin >> firstName >> lastName >> id >> numScores;
      vector<int> scores;
      for(int i = 0; i < numScores; i++){
          int tmpScore;
          cin >> tmpScore;
        scores.push_back(tmpScore);
    }
    Student* s = new Student(firstName, lastName, id, scores);
    s->printPerson();
    cout << "Grade: " << s->calculate() << "\n";
    return 0;
}