The #include directive
The #include directive : C programs are divided into modules or functions. Some functions are written by users, likeus, and many others are stored in the C library. Library functions are grouped category-wise and stored in different files known as Header Files . If we want to access the functions stored in the library, it is necessary to tell the compiler about the files to be accessed. This is achieved by using the preprocessor directive #include as follows : #include<filename> filename is the name of the library file that contains the required function definition. Pre-processor directives are placed at the beginning of a program.