A C++ class library is analogous to a C function library. A C library provides a collection of precompiled functions packaged in a static library. You can link the library with your application and call the library functions directly from within your application. You can use a class library the same way you use a C library, but you also get the added benefits that come with using classes, such as encapsulation, inheritance, and polymorphism. Not only can you use the library classes directly in your application, but you also can derive classes from them that are specifically suited to your application.
The MFC library encapsulates much of the Windows CE application programming interface (API). By organizing related API functions into logical, well-defined classes, MFC for Windows CE makes it easier for C++ developers to take an object-oriented approach to Windows CE programming.