Композиция классов

#include <iostream>
 
using namespace std;
 
class Subject
{
private:
    int numberOfclasses;
    string name, lector, isAlt;
 
public:
    Subject() 
    {
        cout << "Last entry" << endl << endl;
 
    }
    void SetSubject()
    {
        cout << "Add a note about subject" << endl << endl;
 
        cout << "Enter the name of the subject - " << endl;
        cin >> name;
        cout << "Enter the number of classes for this subject - " << endl;
        cin >> numberOfclasses;
        cout << "Alternative or basic - " << endl;
        cin >> isAlt;
        cout << "Lector of this subject - " << endl;
        cin >> lector;
        cout << endl;
    }
    void PrintSubject()
    {
        cout << "Subject: " << name << '\n';
        cout << "Alternative or basic: " << isAlt << "\n";
        cout << "Number of classes: " << numberOfclasses << " classes" << endl;
        cout << "Lector of this subject: " << lector << endl << endl;
        cout << "==========================================" << endl;
    }
 
    int GetnumberOfclasses()
    {
        return numberOfclasses;
    }
    string GetName()
    {
        return name;
    }
    string GetisAlt()
    {
        return isAlt;
    }
 
    ~Subject() {
    }
};
 
class StudentAttendance
{
private:
    int classesAttended, missedClasses;
    string nameOfst;
    string groupName;
public:
 
   
    void SetAttendance()
    {
        cout << "Enter the student's first and last name -  " << endl;
        cin >> nameOfst;
        cout << "Enter the name of the group -  " << endl;
        cin >> groupName;
        cout << "Enter the number of classes attended by this student - " << endl;
        cin >> classesAttended;
        cout << "Enter the number of missed classes by this student - " << endl;
        cin >> missedClasses;
 
        cout << endl;
    }
    void PrintAttendance()
    {
        cout << "Full name of student: " << nameOfst << '\n';
        cout << "Student group name: " << groupName << '\n';
        cout << "Classes attended: " << classesAttended << "\n";
        cout << "Missed classes: " << missedClasses << endl << endl;
        cout << "==========================================" << endl;
    }
 
    string GetGroupName()
    {
        return groupName;
    }
    int GetClassesAttended()
    {
        return classesAttended;
    }
    int GetMissedClasses()
    {
        return missedClasses;
    }
    string GetNameOfst()
    {
        return nameOfst;
    }
    ~StudentAttendance() {
    }
};
 
class GroupJournal : public Subject, StudentAttendance
{
private:
    string nameOfst, subject, missedClasses;
public:
 
 
 
 
 
 
 
 
 
};
 
 
int main()
{
    Subject x;
    x.SetSubject();
    x.PrintSubject();
 
    StudentAttendance y;
    y.SetAttendance();
    y.PrintAttendance();
 
    GroupJournal z;
 
    
    system("pause");
    return 0;
}