Library functions in C: These are built-in functions which are grouped together and placed in a common place called a library. While Each library function in C performs a specific operation.
- All C standard library functions are declared in header files named as file_name.h
- Actually, function declaration and definition of macros are given in all header files.
- These library functions are created by the persons who designed and created C compilers.
- The function declaration, definition for macros are given in all header files.
- We are including these header files in our C program using “#include<file_name.h>” a command to make use of the functions that are declared in the header files.
Library Functions in C
Here we are listing special header files used in C.
- stdio.h
- conio.h
- string.h
- stdlib.h
- math.h
- time.h
- ctype.h
- If you would like to check the remaining all the header files so that you can check inside the “include” directory after the C compiler has been installed in your device.
List of most used Header files in C programming
Check the below table to know all the library functions and header files in which they are declared.
Header file | Description |
---|---|
stdio.h | This is standard input/output header file in which Input/Output functions are declared |
conio.h | This is the console input/output header file |
string.h | All string related functions are defined in this header file |
stdlib.h | This header file contains general functions used in C programs |
math.h | Here all maths-related functions are defined in this header file |
time.h | This header file contains the time and clock-related functions |
ctype.h | All character handling functions are defined in this header file |
stdarg.h | The variable argument functions are declared in this header file |
signal.h | The Signal handling functions are declared in this file |
setjmph.h | This file contains all jump functions |
locale.h | All file contains locale functions |
errno.h | All the Error handling functions are given in this file |
assert.h | All the diagnostics functions are present here. |
Example
#include<stdio.h> #include<ctype.h> #include<math.h> void main() { int i = -10, e = 2, d = 10;/* Variables Defining and Assign values */ float rad = 1.43; double d1 = 3.0,d2 = 4.0; printf("%d\n", abs(i); printf("%f\n",sin(rad)); printf("%f\n", cos(rad)); printf("%f\n", exp(e)); printf("%d\n", log(d)); printf("%f\n", pow(d1, d2)); }
Output
10
0.990105
0.140332
7.389056
-1145744106
81.000000