Define Four Facilities Provided by C Language Preprocessor?

The C language preprocessor provides four separate facilities that you can use as you see fit:

• Inclusion of header files and these are files of declarations that can be substituted into your program.

• Macro expansion, You can define macros, which are abbreviations for arbitrary fragments of C language code, and then the C language preprocessor will replace the macros with their definitions throughout the program.

• Conditional compilation. Using extraordinary preprocessing directives you can exclude or include parts of the program according to various conditions.

• Line control. If you use a program to rearrange or combine source files into an intermediate file which is then compiled you can use line control to inform the compiler of where each source line originally came from.