Problem using a vector iterator in a loop.

The two vectors contain pointers of base class actor, which are used to point to members of two derived classes (player and enemy) and polymorphically call the Update function from the current Enemy, with the current player as an argument.

I believe I have to use pointers, to allow polymorphism (though I read references could be used also, I'd love to be able to do that) since Player's Update function differs from Enemy's.

Code:

---

    ///////////////
    // Game Loop //
    ///////////////
    while (Game.IsOpened())
    {
        if (UpdateClock.GetElapsedTime() > GameLoopTimeLimit)
        {
            for (vector<Actor*>::iterator p_it = Players.begin(); p_it != Players.end(); ++p_it)
            {
                GetInput(Game, p_it);
                for (vector<Actor*>::iterator e_it = Enemies.begin(); e_it != Enemies.end(); ++e_it)
                {
                    *(e_it)->Update(p_it);
                }
            }
            UpdateClock.Reset();
        }
        Render(Game, Camera, Players, Enemies);
    }

---

The error I get is:

Code:

---

/storage/Projects/Recent/Refactored Game/src/main.cpp|156|error: request for member ‘Update’ in ‘* e_it.__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator-> [with _Iterator = Actor**, _Container = std::vector<Actor*>, __gnu_cxx::__normal_iterator<_Iterator, _Container>::pointer = Actor**]()’, which is of non-class type ‘Actor*’|

---

I may not have explained the idea well, but basically a vector of pointers to Player is looped though, and for each player, each Enemy Pointer has it's Enemy Object's Update function run with the current player as an argument.

Any help fixing this code up would be wildly appreciated.

Edit:
I read through and realized I may not have made it clear what I want to do.

I want to call the appropriate Update function, of the Enemy Object, pointed to by e_it. If anyone can help me just decipher that error code, I can work on it myself. I really don't want or expect anyone to re-write my code for me.

Code:

---

*(e_it)->Update(p_it);

---

should be

Code:

---

(*e_it)->Update(p_it);

---

I gave it a go and got...

Code:

---

/storage/Projects/Recent/Refactored Game/src/main.cpp|159|error: no matching function for call to 'Actor::Update(std::vector<Actor*>::iterator&)’|

---

Now, reading the error message, I get that there's no match in the ACTOR class for Update, besides the virtual void Update in the actor class header. I will review some lessons on polymorphism. Thank you for your attention Elkvis!

Here's that virtual definition from actor.h:

Code:

---

virtual void Update() {};

---

Update does not take any arguments, so why do you pass an argument to it?

Go easy on me, but -

Code:

---

virtual void Update() {};

---

Is from Entity::Actor (actor.h), the parent class.

In Actor::Player (player.h) it becomes:

Code:

---

virtual void Update(Actor &Player);

---

And in Actor::Enemy (enemy.h) it's:

Code:

---

virtual void Update(Actor &Player);

---

So, is that my ignorance of polymorphism, that the base virtual method must match arguments with each of it's eventual instantiations in derived classes?

Thank you so much as always for your attention! Edited for typo.

Quote:

---

Originally Posted by M.Richard Tober

So, is that my ignorance of polymorphism, that the base virtual method must match arguments with each of it's eventual instantiations in derived classes?

---

Yes. There is this idea known as the Liskov substitution principle (PDF).

Thank you, this essay is a little above my experience, but I'm going chew over it - and try to bring it back around to my issues. Thank you for (what I consider) a vote of confidence in my ability to learn advanced topics. I am always grateful for yourself and all the mods and users here.