Lets say you were busy handling the WM_PAINT message and suddenly the user types a bunch of stuff on the keyboard. What should happen? Should you be interrupted in your drawing to handle the keys or should the keys just be discarded? Wrong! Obviously neither of these options is reasonable, so we have the message queue, when messages are posted they are added to the message queue and when you handle them they are removed. This ensure that you aren't going to miss messages, if you are handling one, the others will be queued up untill you get to them.
Polymorphism is the ability of different objects to react in an individual manner to the same message. This notion was imported from natural languages. For example, the verb "to close" means different things when applied to different objects. Closing a door, closing a bank account, or closing a program's window are all different actions; their exact meaning is determined by the object on which the action is performed. Most object-oriented languages implement polymorphism only in the form of virtual functions. But C++ has two more mechanisms of static (meaning: compile-time) polymorphism: Operator overloading. Applying the += operator to integers or string objects, for example, is interpreted by each of these objects in an individual manner. Obviously, the underlying implementation of += differs in every type. Yet, intuitively, we can predict what results are. Templates. A vector of integers, for example, reacts differently from a vector of string objects when it receives ...
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