General Class Design Philosophy
Microsoft Windows was designed long before the C++ language became popular. Because thousands of applications use the C-language Windows application programming interface (API), that interface will be maintained for the foreseeable future. Any C++ Windows interface must therefore be built on top of the procedural C-language API. This guarantees that C++ applications will be able to coexist with C applications.
The Microsoft Foundation Class Library is an object-oriented interface to Windows that meets the following design goals:
Significant reduction in the effort to write an application for Windows.
Execution speed comparable to that of the C-language API.
Minimum code size overhead.
Ability to call any Windows C function directly.
Easier conversion of existing C applications to C++.
Ability to leverage from the existing base of C-language Windows programming experience.
Easier use of the Windows API with C++ than with C.
Easier to use yet powerful abstractions of complicated features such as ActiveX controls, database support, printing, toolbars, and status bars.
True Windows API for C++ that effectively uses C++ language features.
For more on the design of the MFC Library, see: