
Preprocessor Directives 481
suMMarY
In this chapter you have studied one of the most useful features of the C language, i.e. the preprocessor
directive. It supports the programmer to write portable programs, which can be executed on different
types of systems. After having gone through this chapter and on execution of programs, you have the
knowledge of the uses of #defi ne, #undef, #include, #line, token pasting and stringiz-
ing operator, conditional compilation through illustrated examples. You have also learnt how to dis-
play programmer’s own error messages using #error directive and making various warnings
on/off displayed by compiler ...