C++ code showing Hierarchical Inheritance

This is the solution for T.U. 2066 Q.N. 3

#include <iostream>

using namespace std;

class Student
{
protected:
    float avg;
public:
    void Show();
};

class ComputerScience:public Student
{
    float OOPL, OS, NM ;
public:
    void GetMarks1();
    void ShowMarks1();
    void CalAvg1();
};

class Mathematics:public Student
{
    float Calculus, LA, Geometry ;
public:
    void GetMarks2();
    void ShowMarks2();
    void CalAvg2();
};

void Student::Show()
{
    cout << endl << "Average=" << avg << endl ;
}

void ComputerScience::GetMarks1()
{
    cout << endl << "Enter marks of:" << endl ;
    cout << endl << "OOPL:"  ;
    cin >> OOPL ;
    cout << endl << "NM:" ;
    cin >>  NM ;
    cout << endl << "OS:" ;
    cin >> OS ;
}

void ComputerScience::ShowMarks1()
{
    cout << endl << "Computer Science:" << endl ;
    cout << endl << "OOPL=" << OOPL << endl << "NM=" << NM << endl << "OS=" << OS << endl ;
}

void ComputerScience::CalAvg1()
{
    avg = (OOPL + NM + OS)/3 ;
}

void Mathematics::GetMarks2()
{
    cout << endl << "Enter Marks of:" << endl ;
    cout << endl << "Calculus:" ;
    cin >> Calculus ;
    cout << endl << "LA:" ;
    cin >> LA ;
    cout << endl << "Geometry:" ;
    cin >> Geometry ;
}

void Mathematics::ShowMarks2()
{
    cout << endl << "Mathematics:" << endl ;
    cout << endl << "Calculus=" << Calculus << endl << "LA=" << LA << endl << "Geometry=" << 
    Geometry << endl ;
}

void Mathematics::CalAvg2()
{
    avg = (Calculus + LA + Geometry)/3 ;
}

int main()
{
    ComputerScience CS;
    CS.GetMarks1();
    CS.CalAvg1();
    Mathematics M;
    M.GetMarks2();
    M.CalAvg2();
    CS.ShowMarks1();
    CS.Show();
    M.ShowMarks2();
    M.Show();
    return 0;
}