What different between blueprint script and c++?

every classes in blueprint has already in unreal database, just search and will find, is that right? What if programming in c++ will it have classes library like that? If I use visual studio with c++, these will not in unreal classes library. s that right? How to create my own classes if i programming in another game engine? can i import my own classes into unreal library? How?

When you programming for Unreal using c++ you can to create your own classes visible by Blueprints using UCLASS declarations. Most of classes and functions exposed in blueprint was created natively using UCLASS and flags. Also you can create custom plugins containing classes and connect these plugins to your games. You can found information about exposing classes to blueprint here

what is class, what is object?

In short class it is about classification and object is an real (or virtual-real) thing.
Class is a description of object capabilities. Also there is an instance word existing. It means some created object that based on some class. For example in game you actually have three players:

  1. Man who play your game - an object in the real world
  2. Player class - Ingame description of what player can do and what stats player have (health, mana, etc…).
  3. Player ingame instance - the character walking inside the virtual world in your game. You can have a lot of instances of player at the same time. It can be multiplayer players or saved player states on a checkpoint.

Classes that you define in c++ can be exported to the engine (it makes them visible in the editor) and then you can create objects(instances) inside game world based on that classes. Also you can create blueprints based on that exported classes

how class was created in unreal? Can I create my own?

now i understand abit c4tnt … how class and object , function related to?any other thing like those that connected in programming?

wait, how we create class? object is 3d model, animation, right? how we create function, and any other?

If you talking about c++ classes maybe this tutorial will help you
https://docs.unrealengine.com/latest/INT/Programming/QuickStart/index.html

Video about plugins
https://www.youtube.com/watch?v=hr9ybCCPw9Y