• A header file is a file with extension .h which contains C function declarations and macro definitions to be shared between several source files.
• There are two types of header files: the files that the programmer writes and the files that comes with your compiler.

A header file called #include contains definitions for many different functions as well as common constants and variable types.

Some common libraries may also be a part of this.

C-language definitions and structures are contained in header files.

The construction and updating of programs are made easier by centralizing information into a header file.

Header files are frequently referred to as include files since #include statements are used to add them to C-language programs.

A header file is a file that contains function prototypes, macro definitions, type definitions, and other declarations that are meant to be shared across multiple source code files. Header files are typically included at the beginning of a C source file using the #include directive. The purpose of using header files in C programming is to separate the declaration of functions, variables, and other entities from their actual implementation. This separation allows for modularity, reusability, and easier maintenance of code.