20个一些窗口编程的小例子，比如如何通过HWND获得CWnd指针,如何获得应用程序主窗口的指针,如何获得指定点的窗口等等的方法。-20 some windows programming small examples, such as how to get through HWND CWnd pointer, pointers on how to get the application s main window, and how to get the method specified point