Cannot call member function std::string Sportist::getIme() without object

Question

I have a class A:

class Sportist{
    private:
        string ime;
        int godina_na_ragjanje;
        int godisna_zarabotuvacka_EUR;
    public:
        Sportist(string i, int g_n_r, int g_z_EUR){
            ime = i;
            godina_na_ragjanje = g_n_r;
            godisna_zarabotuvacka_EUR = g_z_EUR;
        }
        string getIme(){
            return ime;
        }
        int getGodinaNaRagjanje(){
            return godina_na_ragjanje;
        }
        int getGodisnaZarabotuvackaEUR(){
            return godisna_zarabotuvacka_EUR;
        }
};

And class B using the class A as public:

class Fudbaler:public Sportist{
    private:
        int broj_na_odigrani_natprevari;
        int danocna_stapka;
    public:
        Fudbaler(string ime, int godina, int zarabotuvacka, int b, int d)
            :Sportist(ime, godina, zarabotuvacka)
        {
            broj_na_odigrani_natprevari = b;
            danocna_stapka = d;
        }
        float danok(){
            return getGodisnaZarabotuvackaEUR() * danocna_stapka;
        }
        friend ostream& operator<<(ostream &os, Fudbaler F){
            return os << "Ime: " << getIme() << endl
                      << "Godina na raganje: " << getGodinaNaRagjanje() << endl
                      << "Godisna zarabotuvacka(EUR): " << getGodisnaZarabotuvackaEUR() << endl
                      << "Danok sto treba da plati: " << danok();
        }
};

And I get 4 errors as described in title in these lines:

        return os << "Ime: " << getIme() << endl
                  << "Godina na raganje: " << getGodinaNaRagjanje() << endl
                  << "Godisna zarabotuvacka(EUR): " << getGodisnaZarabotuvackaEUR() << endl
                  << "Danok sto treba da plati: " << danok();

cannot call member function 'std::string Sportist::getIme()' without object

cannot call member function 'int Sportist::getGodinaNaRagjanje()' without object

cannot call member function 'int Sportist::getGodisnaZarabotuvackaEUR()' without object

cannot call member function 'float Fudbaler::danok()' without object

Answer 1

i would say the function should be changed to

friend ostream& operator<<(ostream &os, Fudbaler F){
            return os << "Ime: " << F.getIme() << endl
                      << "Godina na raganje: " << F.getGodinaNaRagjanje() << endl
                      << "Godisna zarabotuvacka(EUR): " << F.getGodisnaZarabotuvackaEUR() << endl
                      << "Danok sto treba da plati: " << F.danok();
        }

I am not shure about operator overloading for the std::streams . i usually have done that outside of the class. From your error messages, you need to use the passed Fudbaler variable to access the methods of it.