- Header files store the definitions and rules for different built-in functions in the C program.
- For example, printf(), scanf() functions are defined in stdio.h header file.
- A header file is a file with extention .h which contains C function declarations and macro definitions to be shared between several source files.
- There are two types of header file-files that a programmer writes and a file that comes with your compiler.
- Every header file contains a set of predefined functions, which makes c programming simpler.
- We should include the header file at the start of the program to be able to use the functions defined in the program.
- When header files are added twice in a program, the compiler will process its contents twice.
- This may cause an error when the compiler sees the same structure definition twice.
