can pointers of a mother class type point to its daughter class ?if yes,why?

Question

https://code.sololearn.com/cOpB3W8KSDn5/?ref=app

saw *Enemy e1=&Ninja;
but they two were just of different classes,was this designed?what if I make an "e1++;" action?will e1 jump a sizeof(Enemy) size or a sizeof(Ninja) size or just go wrong?please help!!

Answer 1

hello!
1st) the tag abstract is wrong, sorry..
An abstract class have a pure virtual member function :
virtual void example()=0;
and cannot be instantiated.
An abstract class is meant to be a base class only.

The topic here is polymorphism and you can find information inside the c++ course, if you need help feel free to ask!

2nd) pointer arithmetic on polymorphic is undefined behaviour, absolutely avoid it!
But you can use an array of ponters! like this:

Ninja n;
Monster m;
...

Enemy* enemies[ amount ] ;
enemies[ 0 ] = &n;
enemies[ 1 ] = &m;
....

void nextTurn()
{
for ( int i=0 ; i <amount ; i++){
enemies [ i ]->attack();
}
}

hope it helps!

Answer 2

In your case it doesn't matter because the classes are the same size. But in general 'ptr++' will jump by sizeof(Enemy), which can get you into trouble if Ninja is bigger, yes!

Answer 3

thanks guys ! I'm so much grateful ..