inheritance and overloading

/*AndroidPhone erbt von MobilePhone wo << überschrieben wurde und die entsprechenden Getter-Klassen ausprogrammiert sind*/

#pragma once
#include "MobilePhone.h"

class AndroidPhone: public MobilePhone {
private:
    string AndroidOSVersion;
public:
    AndroidPhone(int index, string number, string version);
    AndroidPhone (string os, MobilePhone mp);
    string getOS();
    friend ostream& operator<<(ostream& out, const AndroidPhone &mp);

};

--------------


#include "AndroidPhone.h"


AndroidPhone::AndroidPhone (int i, string num, string os): AndroidOSVersion(os),MobilePhone(i,num){};
AndroidPhone::AndroidPhone (string os, MobilePhone mp):AndroidOSVersion(os),MobilePhone(mp){};

string AndroidPhone::getOS() {

    return this->AndroidOSVersion;
}

ostream& operator<<(ostream& out, const AndroidPhone& ap) {
    return out << ap.getIndex() << " " << ap.getPhoneNumber() << " " << ap.AndroidOSVersion <<endl;
}