windows - multithreading and multitasking o.s dos is stranger to these concepts.
traditional dos programming is procedural, meaning that your program starts at one place, and steps through the code sequentially.
windows programming is event-based, meaning that each time an event (like a button-click) occurs; a handler is invoked to produce a response. the difference can be frustrating, since in event-driven code you can inadvertently have several functions running simultaneously on the same data.
3．what is the advantage of windows?
gui, multitasking, multithreaded o.s., you can also add: supports a vast variety of devices and has a large base of developers and software.
4．what does winmain and wndproc do?
wndmain is the entry point for a win32 app (like main() would be in a dos/unix app). it is used in almost exactly the same way, except that you pass it a lot of worthless params that your code probably won't use anyhow.
wndproc (aka "window procedure") is a function that will be run by your program to process events that occur within it. the wndproc is specified when you call createwindow() and usually consists of several nested switch() statements.
5．how does user input are trapped in windows?
6．define and explain com.
com is a binary standard on microsoft (and some unix platforms) that enables objects to interoperate in a networked environment regardless of the language in which they were developed or on which computers they reside. com allows an object to expose its functionality to other components and to host applications. it defines both how the object exposes itself and how this exposure works across processes and across networks. com also defines the object's life cycle.
7．what is iunknown and what are its three parts?
iunknown is the basic com interface on which all others are based on.
the three methods of iunknown are
1) queryinterface
2) addref
3) release
