Jeje sorry if i seemed to be testing your knowledge is not about that.
I understand that a virtual function's purpose is so that when you have several classes and you have the same function for several of them, when the program is running it understands to what object the specified function is applied to (what you explained here). Its just that while reading about abstract classes, they tell me that the pure virtual functions have to be implemented by a derived class, so I wonder if that is done to force someone to implement something that maybe I dont know how to implement. They didnt give me a reason so I guessed it was for that.