#include <iostream>
#include <cstdlib>

using namespace std;

class speaker1_int;
class speaker2_int;

class speaker1_int{
public:
    virtual void como_estas(speaker2_int* spk2)=0;
    virtual void Hola(speaker2_int* spk2)=0;
};

class speaker2_int{
public:
    virtual void mucho_gusto(speaker1_int* spk1)=0;
    virtual void bien_y_vos()=0;
    virtual void start(speaker1_int* spk1)=0;
};

class speaker1: public speaker1_int{
private:
    void Hola(speaker2_int* spk2){
        cout << "Hola!" <<endl;
        spk2->mucho_gusto(this);
    }
    void como_estas(speaker2_int* spk2){
        cout << "Como estas?" << endl;
        spk2->bien_y_vos();
    }
};

class speaker2: public speaker2_int{
private:
    void mucho_gusto(speaker1_int* spk1){
        cout << "Mucho gusto" <<endl;
        spk1->como_estas(this);
    }
    void bien_y_vos(){
        cout << "Bien y vos?" <<endl;
    }
public:
    void start(speaker1_int* spk1){
        spk1->Hola(this);
    }
};

int main (){
    speaker1* spk1;
    speaker2* spk2;

    spk1 = new (speaker1);
    spk2 = new (speaker2);

    spk2->start(spk1);
    delete spk1;
    delete spk2;

    return EXIT_SUCCESS;
}