Introuduction to polymorphism.

#include <iostream>

using namespace std;

class Enemy
{
protected:
    int attackPower;

public:
        void setAttackPower(int a)
        {
          attackPower = a;
        }
};

class Ninja : public Enemy
{
public:
        void attack()
    {
        cout << "I am a ninja, ninja chop! -" << attackPower << endl;
    }
};

class Monster : public Enemy
{
public:
        void attack()
    {
        cout << "Monster must eat you!!! -" << attackPower << endl;
    }
};

int main()
{
    Ninja n;
    Monster m;
    Enemy *enemy1 = &n;
    Enemy *enemy2 = &m;
    enemy1->setAttackPower(21);
    enemy2->setAttackPower(43);
    n.attack();
    m.attack();
}