21.3. Windiff and merging code
In the old days it was customary to use the Unix diff or the DOS fc utilities for this. Now it is more common to use a graphically interfaced tool that comes with your compiler.
Microsoft Visual Studio has a utility called Windiff which is pretty easy to use. The tool is still shipped with Visual Studio.NET, but in a default installation, Windiff will normally not be installed, so you may need to run through Visual Studio setup process to select this particular tool to be added onto your machine. It is part of the group of tools added by selecting Visual C++ Tools | Win32 Platform SDK in the Setup dialog.
As Windiff is an older program, it may not appear on your Start | Programs | Microsoft Visual Studio ...