In C, the #include statement is a preprocessor directive that is used to include header files in the program. A header file contains function prototypes, macro definitions, and other declarations that are necessary for the program to compile and run correctly.
The syntax for using the #include statement is:
The first syntax is used for standard library header files, which are typically located in the system’s include directory. The second syntax is used for user-defined header files, which are located in the same directory as the source code or in a directory specified by the -I option of the compiler.
Including header files using the #include statement is important because it allows the program to access the necessary declarations and definitions that are not included in the main source file. This helps in making the program more modular and reusable, by separating the implementation details from the interface.