Pointer

Question

why need pointer when i can use n.setAttack(5);//basic polymorphism lesson code? what is actually function of pointer?

Answer 1

This is polymorphism as I understand it.
You are operating on a base object, Enemy, that doesn't know about the implementation, only that attack is virtual and will be determined at run time.
The benefit is you can write methods accepting the base type rather than individually for each sub.

Answer 2

int main() {
Ninja n;
Monster m;
Enemy *e1 = &n;
Enemy *e2 = &m;
e1->setAttackPower(20);
e2->setAttackPower(80);
n.attack();
m.attack();
}
/* Output:
Ninja! - 20
Monster! - 80
*/