Header file

Introduction

The C provides a large number of C functions as libraries. Some of these implement frequently used operations, while others are very specialized in their application.

Wise programmers will check whether a library function is available to perform a task before writing their own version.

This will reduce program development time. The library functions have been tested, so they are more likely to be correct than any function which the programmer might write.

This will save time when debugging the program. For using these files ,certain files are needed to be included in the program which make call to these functions.

These files are known as Header files and they contain macro definition ,type definition, and function declarations.

These header files usually have an extension .h as stdio.h, ctype.h, string.h, math.h, stdlib.h, stdarg.h, time.h etc.