#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
#include <cmath>
#include <ctime>
#include <cctype>

using namespace std;


class Animal {
    public:
        virtual void makeSound() = 0;
};
class Dog : public Animal {
    public:
        virtual void makeSound(){
            cout << "Woof!" << endl;
        }
};
class Cat : public Animal {
    public:
        virtual void makeSound(){
            cout << "Meaaaaw!" << endl;
        }
};
class Parrot : public Animal {
    public:
        virtual void makeSound(){
            cout << "Hello, I'm a parrot!" << endl;
        }
};

int main(){

    vector<Animal *> zoo;

    srand(time(NULL));
    for(int i = 0; i < 10; i++){
        /*
        Animal *a;
        switch(rand()%3){
            case 0:
                a = new Dog();
                break;
            case 1:
                a = new Cat();
                break;
            case 2:
                a = new Parrot();
                break;
        }
        zoo.push_back(a);
        */
        zoo.push_back(new Parrot());

    }

    for(int i = 0; i < 10; i++){
        zoo[i]->makeSound();
    }

    for(int i = 0; i < 10; i++){
        delete zoo[i];
    }


    return 0;
}