"stdio.h" and "stdlib.h" are both standard C library header files.
"stdio.h" is the header file for the C standard input/output library, which contains functions for performing input and output operations, such as printf and scanf, specifically for input/output from/to files and streams. These functions are used for reading and writing data to and from the standard input and output streams (stdin and stdout), as well as to and from files and other streams. While "stdlib.h" contains functions for general purpose functions, including memory allocation and deallocation, process control, conversions, and others. Additionally, <stdio.h> also contains functions for formatting and parsing input and output, such as fprintf, fscanf, sprintf and sscanf. getc and putc are also functions of stdio.h, which are used for reading and writing individual characters. Additionally, stdio.h also contains functions for working with files, such as fopen, fread, and fwrite. stdio.h is widely used in C programs as it contains functions that are essential for performing input and output operations.
In C, the standard input and output streams (stdin and stdout) are treated as files, even though they may not be physical files on disk. The functions in "stdio.h" such as printf and scanf are used for input and output operations on these standard streams, as well as on other streams such as files.
<stdlib.h> contains other types of functions as well, such as atoi, exit, and rand, but it's true that malloc and free are probably the most commonly used functions from this library for memory allocation and deallocation. This header file contains functions such as malloc and free for memory management, atoi for string to integer conversion, and exit for exiting from a program. Additionally, it also contains functions for converting strings to numerical values (such as atoi and atof) and functions for random number generation (such as rand and srand). It is true that you only use stdlib.h when you need to allocate memory in your program but it also contains other general-purpose functions that can be useful in different situations.
Header files often contain a combination of function declarations, constants, variables, macros, and even struct and enum definitions. They are used to make declarations and definitions available to multiple source files in a program. By including the appropriate header file in a source file, the compiler can access the function prototypes, constants, variables, etc. defined in the header file and use them while compiling the source file. This helps to organize and modularize the code and makes it easier to manage and maintain large projects.
