VC++ tutorial

Message driven: Messages are the heart of every windows program. A good understanding of how the windows operating system sends messages will be a great help to you as you write your own programs.

Messages are delivered to all windows that must receive events. windows program generates a larger number of messages. Messages sent to a window are placed in a queue, and a program must examine each message in turn. A window procedure is function that handles messages sent to it. when a window procedure receives the messages, the parameters passed along with the message are used to help to decide how message should be handled.

Event driven:Event Driven: in the classical approach to programming, events happen in a pre-defined sequence. in fact, classical programmers go the extent of defining programs as sets of instructions that are executed sequentially by the computer.

Event-driven programming is where the program responds to events rather than follow a sequential course of instructions. Event-driven programming is especially useful in object-oriented environments and where graphical user interfaces are being constructed. Most high-level GUI APIs (OWL, MFC, Turbo Vision, etc) use event-driven programming to embed basic features into every program.