SIMPLE ARRAY OF OBJECT AND DATA MODIFICATION

 #include <iostream>

using namespace std;

#include <conio.h>

class base

{

protected:

    string name;

    long long int rollno, phno;

    string address;

public:

    void getdata()

    {

        cout << "\nENTER NAME:" << endl;

        cin >> name;

        cout << "\nENTER ROLL NO.:" << endl;

        cin >> rollno;

        cout << "\nENTER PHONE NO. :"

             << endl;

        cin >> phno;

        cout << "\nENTER ADDRESS:"

             << endl;

        cin >> address;

    }

};

class derived : public base

{

private:

    long long int s1, s2, total;

public:

    void getdataderived()

    {

        cout << "\nENTER MARKS OF FIRST SESSIONAL:" << endl;

        cin >> s1;

        cout << "\nENTER MARKS OF SECOND SESSIONAL::" << endl;

        cin >> s2;

        total = (int)(s1 + s2);

    }

    void showdetails()

    {

        cout << "NAME IS " << name << endl;

        cout << "ROLL NO. IS " << rollno << endl;

        cout << "PHONE NO. IS " << phno << endl;

        cout << "ADDRESS IS " << address << endl;

        cout << "TOTAL MARKS ARE  " << total << endl;

    }

};

int main()

{

    system("cls");

    int size;

    cout << "ENTER THE NUMBER OF STUDENTS YOU WANNA SAVE DATA OF\n";

    cin >> size;

    derived obj[size];

    for (int i = 0; i < size; i++)

    {

        cout << "ENTER THE DATA OF STUDENT: " << i + 1 << endl;

        obj[i].getdata();

        obj[i].getdataderived();

        system("cls");

    }

    system("cls");

    cout << "DATA OF STUDENT BEFORE ANY MODIFICATIONS\n";

    for (int i = 0; i < size; i++)

    {

        cout << "DATA OF STUDENT " << i + 1 << endl;

        obj[i].showdetails();

        cout << endl;

    }

    int serial;

    cout << "ENTER SERIAL NUMBER OF STUDENT YOU WANNA MODIFY DATA OF\n";

    cin >> serial;

    cout << "ENTER THE NEW DATA\n";

    obj[serial - 1].getdata();

    obj[serial - 1].getdataderived();

    system("cls");

    cout << "DATA OF STUDENT AFTER MODIFICATIONS\n";

    for (int i = 0; i < size; i++)

    {

        cout << "DATA OF STUDENT " << i + 1 << endl;

        obj[i].showdetails();

        cout << endl;

    }

    return 0;

}