Library Functions in C Programming

C functions are broadly classified into two major categories, they are, Library or Built – in Functions & User Defined Functions.

Library functions are those type of functions which are already defined, compiled and stored in different header file of standard C library.

Library functions are part of C compiler and ships with compiler. We can use these functions as required by including their respective header file and we need not to worry about their source code or how they accomplish their tasks.

Examples of library functions are: printf(), scanf(), sin(), sqrt(), getch(), getche(), gets() etc.

printf(), scanf() are defined in stdio.h header file.

sin(), sqrt() are defined in math.h header file.

getch(), getche() are defined in conio.h header file.