Suppose we have a world as a class, and some agents in the world. Agents are also objects. The problem with OO is that when we want to implement the world we also have to make an instance of the agent within the world class. It's obvious that the agent within the class should know almost everything about it's world (it has a lot of examples around us), but it do nothing unless we send him a reference/pointer of the world class.
Isn't it a problem with Object Oriented Concepts?

Either make all the stuff in World that the agent needs to know about public, or if you feel it needs to be private you can use some language construct to give Agent access to it. In java you could make Agent an inner class (terminoligy?) of World, or in c++ you can use "friend". You can instantiate an Agent with a {pointer|reference} to an instance of World.

Thanks, I think this answers to part of my question. But human -as an agent in the world- can not be an inner class of the world, because it's an independent object, and should not place within the world class. What about this problem?

I think your talking about nested classes which I find interesting(learned something new), I found some information for you that basically says you can make the nested class friends with the outer class and have access to it's members.

Also if the nested class is declared in the public section it will be visible to other classes and as such you can create independent instances of those objects.

http://www.icce.rug.nl/documents/cpl...lusplus16.html

Thanks

After reading you original post again it sounds like maybe you just need the world class to be a friend of the agent class?

your question really asks about the rules of inheritance and abstract classes, and does not apply to real world examples. The world doesn't necessarily 'classify' easily; we cannot organize what 'the world' consists of in a finite way. so there IS no inheritance nor is there real classification except in the loosest sense of the word.

remember -- OO is based on classification, a way of organizing information for OUR understanding. We do not understand what 'the world' is in every definition (macrocostic to microcostic) so it makes for a bad example.

just because we are of the world, doesn't mean we are the world.

instead, the world is comprised of us. that's the real gotcha.




J