Obiektówka C++ zadania

#include <iostream>
#include <string>

using namespace std;
class Samochod
{
private:
    double cena;
    int moc, maksPredkosc;
public:
    Samochod()
    {
        cena = 0;
        moc = 0;
        maksPredkosc = 0;
    }

    Samochod(double cena, int moc, int maksPredkosc)
    {
        this -> cena = cena;
        this -> moc = moc;
        this -> maksPredkosc = maksPredkosc;
    }

    void getValues()
    {
        cout << "Cena: " << cena << " Moc: " << moc << " Maks. predkosc: " << maksPredkosc << endl;
    }
};

class Uczen
{
private:
    string imie, nazwisko;
    int klasa, ocenaKoncowa;
public:
    Uczen(string imie, string nazwisko, int klasa, int ocenaKoncowa) {
        this->imie = imie;
        this->nazwisko = nazwisko;
        this->klasa = klasa;
        this->ocenaKoncowa = ocenaKoncowa;
    }
    void getValues()
    {
        cout << imie << " " << nazwisko << " Klasa: " << klasa << " Ocena koncowa: " << ocenaKoncowa << endl;
    }
};

class PPP
{
private:
    double a, b, c, wynik;

public:
    PPP(int a, int b, int c)
    {
        this->a =a;
        this->b=b;
        this->c=c;
        this->wynik = Pp();
    }
    double Pp()
    {
        return 2*a*b+2*a*c+2*b*c;
    }
    void getValues()
    {
        cout<< "Pole powierzchni prostopadloscianu (a:"<<a<<",b:"<< b << ",c:"<<c<<" wynosi: " << wynik << ")" << endl;
    }

};

class Rachunek
{
private:
    string data;
    double wartoscNetto, wartoscBrutto, podatek;
public:
    double brutto()
    {
        return wartoscNetto - wartoscNetto*0.23;
    }

    double podatekVat()
    {
        return wartoscNetto*0.23;
    }

    Rachunek(string data, double wartoscNetto)
    {
        this->data = data;
        this->wartoscNetto = wartoscNetto;
        this->wartoscBrutto = brutto();
        this->podatek = podatekVat();
    }

    void getValues()
    {
        cout << "Data:" << data << endl;
        cout << "Wartosc stawki netto:" << wartoscNetto << endl;
        cout << "Wartosc stawki brutto: " << wartoscBrutto << endl;
        cout << "Podatek: " << podatek;
    }
};

class MyWater
{

private:
    int large, medium, small;
public:
    double largeCapacity = 2, mediumCapacity = 1, smallCapacity = 0.5;
    void setLarge(int i) { large = i; }
    int getLarge() { return large; }
    void setMedium(int i) { medium = i; }
    int  getMedium() { return medium; }
    void setSmall(int i) { small = i; }
    int getSmall() { return small; }


    void addLarge(int i) { large += i; }
    void addMedium(int i) { medium += i; }
    void addSmall(int i) { small += i; }

    double iloscWody()
    {
        return getLarge()*largeCapacity + getMedium()*mediumCapacity+getSmall()*smallCapacity;
    }
    void getValues()
    {
        cout << "Mamy teraz " << iloscWody() << " litrow wody." << endl;
        cout << "Duzych butelek: " << getLarge() << endl;
        cout << "Srednich butelek: " << getMedium() << endl;
        cout << "Malych butelek: " << getSmall() << endl;
    }

};

int main()
{
    Samochod samochod(500,50,50);
    samochod.getValues();

    cout<<endl;

    Uczen uczen("Hakuna", "Matata", 3, 4);
    uczen.getValues();

    cout<<endl;

    PPP ppp(4,5,6);
    ppp.getValues();

    cout<<endl;

    Rachunek rachunek("15.05.2019", 2137);
    rachunek.getValues();

    cout << endl;
    cout << endl;

    MyWater myWater;
    myWater.setLarge(5);
    myWater.setMedium(10);
    myWater.setSmall(13);
    myWater.getValues();

    cout << endl;
    return 0;
}