When programming for Windows, you're really engaged in a type of object-oriented programming. This is most evident in the object you'll be working with most in Windows_ the object that gives Windows its name, the object that will soon seem to take on anthropomorphic characteristics, the object that may even show up in your dreams, the object known as the ”window.“
Windows are rectangular objects on the screen. A window receives user input from the keyboard or mouse and displays graphical output on its surface.
An application window usually contains the program's title bar, menu, sizing border, and perhaps some scroll bars. Dialog boxes are additional windows. Moreover, the surface of a dialog box always contains several additional windows called ”child windows.“ These child windows take the form of push buttons, radio buttons, check boxes, text entry fields, list boxes, and scroll bars.
The user sees these windows as objects on the screen and interacts directly with these objects by pushing a button or scrolling a scroll bar. Interestingly enough, the programmer's perspective is analogous to the user's perspective. The window receives this user input in the form of ”messages“ to the window. A window also uses messages to communicate with other windows.
Understanding these messages is one of the hurdles you'll have to jump in becoming a Windows programmer.