They are the files that are generated by the compiler as the source code file is processed.The header files are added at the start of the source code so that they can be used by more than one function of the same file. Vi) conio.h – used for clearing the screen. V) alloc.h – used for dynamic memory allocation. Iv) math.h – used for mathematical functions. Iii) stdio.h – used for giving standardized input and output. Ii) stdlib.h – used for some miscellaneous functions. I) string.h – used for handling string functions. If we need to modify anything then changes are made only in the subroutines after which all the changes will be reflected.Ĭ provides us with some standard header files which are available easily. This tells us that including a header file will make it easier at all levels of the program. For doing this, he will have to only change the source file for the subroutines, recompile the source code and then recompile and re-link the program. At times the programmer may want to change or add the subroutines and reflect those changes in all the programs. To do this, he would just compile the code of the subroutine once and link to the resulting object file in any file in which the functionalities of this subroutine are required.Ģ. At times the programmer may want to use the same subroutines for different programs. They contain the C function declarations and macro definitions that are shared between various source files.ġ.

It may also contain other source code files. main() is the starting point of the program.It defines the main and many more functions written in C. The extension for these kind of files are '.c'.

This file includes the source code of the program.

A C program uses four types of files as follows:

Conio library source code