C Library Function

C Library function or standard C library functions are inbuilt functions which are grouped togather and placed in a common place called library or Standard  library. Each library function performs specific operation. The prototype and data definitions of all C standard library functions are declared in many header files which are saved as file_name.h, and they must be included in the program to access them. For example  to use printf() and scanf() function we must need to include the stdio.h header file.
#include <stdio.h>

int main() {
  printf("Hello world.\n");
}
List Of Header Files :

The below table shows the list of most used header files in C programming language.

Header File Description
stdio.h Standard Input/Output functions
conio.h This is console input/output header file (Only in windows)
string.h String handling functions
stdlib.h Standard Utility functions
math.h Mathematics functions
time.h Date and time functions
ctype.h Character type functions
stdarg.h Variable arguments handling functions
signal.h Signal handling functions
setjmp.h Jump functions
locale.h Localization functions
errno.h Error handling functions are given in this file
assert.h This contains diagnostics functions


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