Header files “stdio.h” and “stdlib.h” in C

stdio.h

The header file stdio.h stands for Standard Input Output. It has the information related to input/output functions.

Here is the table that displays some of the functions in stdio.h in C language,

Sr.No.	Functions & Description
1	printf() It is used to print the strings, integer, character etc on the output screen.
2	scanf() It reads the character, string, integer etc from the keyboard.
3	getc() It reads the character from the file.
4	putc() It writes the character to the file.
5	fopen() It opens the file and all file handling functions are defined in stdio.h header file.
6	fclose() It closes the opened file.
7	remove() It deletes the file.
8	fflush() It flushes the file.

Here is an example of stdio.h in C language,

Example

Live Demo

#include<stdio.h>

int main () {
   char val;

   printf("Enter the character: \n");
   val = getc(stdin);
   printf("Character entered: ");
   putc(val, stdout);

   return(0);
}

Output

Here is the output

Enter the character: s
Character entered: s

stdlib.h

The header file stdlib.h stands for Standard Library. It has the information of memory allocation/freeing functions.

Here is the table that displays some of the functions in stdlib.h in C language,

Sr.No.	Functions & Description
1	malloc() It allocates the memory during execution of program.
2	free() It frees the allocated memory.
3	abort() It terminates the C program.
4	exit() It terminates the program and does not return any value.
5	atol() It converts a string to long int.
6	atoll() It converts a string to long long int.
7	atof() It converts a string to floating point value.
8	rand() It returns a random integer value

Here is an example of stdlib.h in C language,

Example

Live Demo

#include <stdio.h>
#include<stdlib.h>

int main() {
   char str1[20] = "53875";
   char str2[20] = "367587938";
   char str3[20] = "53875.8843";

   long int a = atol(str1);
   printf("String to long int : %d\n", a);

   long long int b = atoll(str2);
   printf("String to long long int : %d\n", b);

   double c = atof(str3);
   printf("String to long int : %f\n", c);
   printf("The first random value : %d\n", rand());
   printf("The second random value : %d", rand());

   return 0;
}

Output

Here is the output

String to long int : 53875
String to long long int : 367587938
String to long int : 53875.884300
The first random value : 1804289383
The second random value : 846930886