PreC uses the compiler as the preprocessor by changing each preprocessor statement to a C stattement and changuing the original code to a type of print statement. The resulting code is compilede and run and as a result the preprocessor statements are executed and the original program printed back. This gives the user the full power of the C/c++ compiler to be used as a preprocessor.
To see posssible application please look in the documentation for the sample of sorted initialization and generation of CRC at compile time