#include <iostream>
#include <vector>

using namespace std;

class Animal
{
public:
  ~Animal() = default;
  virtual string name() const = 0;
  virtual string noise() const = 0;
};

class Cat : public Animal
{
public:
  string name() const { return "cat"; }
  string noise() const { return "miow"; }
};

class Dog : public Animal
{
public:
  string name() const { return "dog"; }
  string noise() const { return "woff"; }
};

class Cow : public Animal
{
public:
  string name() const { return "cow"; }
  string noise() const { return "moo"; }
};

void print_verse(Animal const* animal)
{
  cout << "Old MacDonald had a farm, E-I-E-I-O,"
       << endl
       << "And on that farm he had a "
       << animal->name() << ", E-I-E-I-O,"
       << endl
       << "With a " << animal->noise() << " " << animal->noise()
       << " here and a " << animal->noise() << " " << animal->noise()
       << " there"
       << endl
       << "Here a " << animal->noise()
       << ", there a " << animal->noise()
       << ", everywhere a " << animal->noise()
       << " " << animal->noise()
       << endl
       << "Old MacDonald had a farm, E-I-E-I-O."
       << endl
       << endl;
}

int main()
{
  // Create a vector with Animals
  vector<Animal*> v;

  // Insert at least three different animals in the vector
  v.push_back(new Cow);
  v.push_back(new Cat);
  v.push_back(new Dog);

  // Iterate the vector and call print_verse with each animal
  for ( Animal const* a : v )
    print_verse(a);

  // Clean up any allocated memory
  for ( Animal const* a : v )
    delete a;
  
  return 0;
}