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
Updated on: 2020-06-25T09:39:07+05:30

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