Animal 'inheritance'

//animal.h
#ifndef ANIMAL_H
#define ANIMAL_H

#include <string>
class Animal
{
public:
    Animal(std::string animalClass_, std::string type_, unsigned age_);
    std::string getAnimalClass() {return animalClass;}
    std::string getType() {return type;}
    unsigned getAge() {return age;}

protected:
    std::string type;
    std::string animalClass;
    unsigned age;
};

#endif // ANIMAL_H

//animal.cpp
#include "animal.h"

Animal::Animal(std::string animalClass_, std::string type_, unsigned age_) :
    type(type_),
    animalClass(animalClass_),
    age(age_)
{}

//mammal.h
#ifndef MAMMAL_H
#define MAMMAL_H
#include "animal.h"

class Mammal : public Animal
{
public:
    Mammal(std::string type_, std::string name_, unsigned age_);
    std::string getName() {return name;}
protected:
    std::string name;
};

#endif // MAMMAL_H

//mammal.cpp
#include "mammal.h"

Mammal::Mammal(std::string type_, std::string name_, unsigned age_) :
    Animal("Ssaki", type_, age_),
    name(name_)
{}

//dog.h
#ifndef DOG_H
#define DOG_H

#include "mammal.h"
class Dog : public Mammal
{
public:
    Dog(std::string name_, std::string owner_, unsigned age_);
    std::string getOwnerName() {return owner;}
private:
    std::string owner;
};

#endif // DOG_H

//dog.cpp
#include "dog.h"

Dog::Dog(std::string name_, std::string owner_, unsigned age_) :
    Mammal ("Pies", name_, age_),
    owner(owner_)
{}

//main.cpp
#include <iostream>
#include "dog.h"

using namespace std;

int main()
{
    Dog leos("Leo", "Jakub Warchol", 4);

    cout << "Gromada: " << leos.getAnimalClass() << endl;
    cout << "Gatunek: " << leos.getType() << endl;
    cout << "Imie: " << leos.getName() << endl;
    cout << "Wlasciciel: " << leos.getOwnerName() << endl;
    cout << "Wiek: " << leos.getAge() << endl;

    return 0;
}