Difference between header files "stdio.h" and "stdlib.h" ?

A header file is a source file with the .h extension. The header files include function prototypes or functional declarations, while the source code contains constants, macros, and system-wide variable declarations. Whenever we need to define a function, we manually include the file called the header that contains where the function is declared.

In a program, there are two distinct kinds of header files defined:

Predefined: A predetermined header file is commonly referred to as a system-specified header file.

User-defined header file: A customer-defined header file is specified by the user.

What is stdio.h?

In C and C++ programming languages, the stdio.h header stands for "standard input-output header". It's a basic header file that contains key functions, macros, and descriptions for these languages' input and output activities. The following is a comprehensive section of the stdio.h header:

stdio.h's primary objective is to offer a uniform interface for input and output operations. It offers a variety of functions and macros for interacting with input devices (such as keyboards), output devices (such as screens), and file processing.

Contents of stdio.h:

I/O functions: It include printf(), scanf(), fprintf(), fscanf(), sprintf(), snprintf(), fopen(), fclose(), fread(), fwrite(), and others. These procedures are necessary for reading user input, presenting output on the display, and performing tasks with files.

File Handling: Operations such as fopen(), fclose(), fread(), fwrite(), and others help file operations such as accessing files, reading and writing to them, closing files, and so on.

Error Handling: Functions such as perror() and feof() aid in handling errors and verifying end-of-file scenarios while reading files.

Formatted Input and Output: printf() and scanf() are frequently used for structured output and input, respectively. They enable particular data formatting while displaying on the screen or receiving input.

Buffered I/O Operations: Functions such as setbuf(), setvbuf(), and others assist in regulating multiplexing for input and output streams.

Constants and Macros: It specifies several constants such as NULL, file access modes ("r", "w", "a", and so on), and the FILE type that is used in file management.

What is stdlib.h?

The stdlib.h header, short form "standard library", is a key header file in the programming languages C++ and C that contains a range of functions, macros, and types for general-purpose code operations. Memory management, program control, conversions, and additional useful actions are all available. We'll go into the details of stdlib.h:

The major goal of stdlib. h is to provide a standardized set of functions that handle a variety of activities that are not immediately linked to input/output but are essential for general-purpose programming as well as application development.

Contents of stdlib.h

Memory Allocation and Deallocation: malloc(), calloc(), realloc(), and free(): These methods allow for the dynamic allocation of memory and the deallocation during the running of the program. They let applications manage memory during runtime, allowing for the most effective use of memory resources.

Random Number Generation: rand() and srand(): These methods help generate pseudo-random numbers, which are important in simulations, gaming applications, encryption, and other scenarios that need uncertainty.

atoi(), atof(), itoa(): Algorithms for converting characters to integers, floats, and vice versa.

strtol(), strtoul(), and strtod(): These functions convert strings to long integers as well, unsigned long integers and doubles as well.

bsearch() and qsort(): Functions used for searching and arranging arrays.

Program Control and Termination: exit() and abort() are functions for ending the execution of a program.

atexit(): Registers schedules that will be run after the program terminates to execute cleaning chores.

System(): Runs shell commands from within a C/C++ application, enabling interaction with the underlying OS.

Utility Functions: abs(), labs(), llabs(): Functions for calculating absolute values.

div(), ldiv(), and lldiv(): These functions are integer division and remainder calculation functions.

exit(): It is used for terminating the process.

Main Differences between the stdio.h and stdlib.h:

Below are the differences between stdio.h and stdlib.h header files:

Features	stdio.h	stdlib.h
Functions	It provides mostly input/output functions, such as *reading* from and *writing* to files, structured printing, scanned input, and so on.	This file contains functions mostly related to memory allocation, string translation to numerical values, random number generations, and program management.
File Operations	Allows for the opening (fopen), closing (fclose), reading (fread), and writing (fwrite) of files.	The focus of stdlib.h is *handling memory* and other utility functions, rather than the operation of files.
Memory Management	This header file does not handle memory allocations or *deallocation functions*; instead, it focuses on input/output activities.	It provides fundamental functions for the dynamic allocation of memory and deallocation, such as malloc, calloc, realloc, and free.
Conversion functions	It does not provide functions for transforming data types or strings to numeric values.	It provides string-to-number *conversion methods* such as atoi (ASCII to integer) and atof (ASCII to float).
Error handling	It provides notification of errors and output services such as perror and fprintf.	It contains functions such as exit and abort for ending the program or managing serious failures.
Control flow	It does not include functions that directly regulate program flow or terminating.	It provides methods such as *exit and abort* for ending program execution or managing serious failures.