Whenever you see a C program code, have you noticed the words include stdio h, math.h and such terms in it? These words are nothing but library functions. Library functions help every code run and execute the result a user wants.
Each function has a purpose on its own but some of them with similar names tend to confuse users. That said, C language’s header files stdio.h and stdlib.h are two important functions that usually end up confusing programmers.
Stdio.h is a header file that helps coders to assign the input values and output values. Stdlib.h is another header file that provides the coders with memory-based function calls.
For a more detailed understanding of these two important header files, we’ve curated a blog where everything, starting from what a C language is, its library functions, to the difference between stdlib.h and stdio.h are covered.
Without further ado, let’s enrich our coding knowledge.
Difference Between Header Files Stdio.h and Stdlib.h
Library functions help users to work with code with pre-saved functions that saves time. Among these functions, stdio.h and stdlib.h are prominent C programming language’s prominent ones. Here are the differences between these two header files that will enrich our coding knowledge.
Definitions
The header file Stdio.h stands for Standard Input and Output. As the name suggests, all data related to the input values and the output values given and received by the user are present. Most of the C programs start with include stdio h syntax as it allows the code to give the required result.
The other header file stdlib.h stands for a standard library where basic functions of C language are stored. It typically is used to exit, manipulate, analyze or show errors in a code.
Functions
Both header files are necessary in writing a C program because they have distinctive and important features. Some of the notable attributes are,
Stdio.h
Stdio.h header file has around 40+ methods to run the program and users tend to use this header to get the desired result.
This header specifically includes three variables, certain macro methods and other definitions. These aspects help the code to inculcate both output and input in C operations. The syntax we use is,
#include <stdio.h>
The most common processes undertaken by stdio is printing and scanning. For these two we use the functions printf as well as scanf. With the help of these functions, the texts inside the program come out as a result.
The stdio.h library uses a communication device called streams. Streams helps to travel information between code and hardware.
Stdlib.h
Another common header file in C language is the stdlib.h file. When we want to declare certain processes like allocating memory, declaring algorithms and such, we must include stdlib h. Even in this header file, we have certain data types as well as macros. The syntax is,
#include <stdlib.h>
Let’s take an array as the input. With the help of the qsort() which is a function from stdlib.h, we can sort the array and later print it.
We will first input the stdlib.h in the code’s first line. Then, we need to find the array’s size before we specify the needed memory for it. To allocate the memory, we will make use of the function malloc which will specify space for n digits.
Once we finish the code, we have to free the used space or else leakage of space will occur. Thus for this purpose, we will use the atexit function and register free_array function. In case, the procedure fails, we will make use of perror function which will show all the errors to the user. The error will be sent to stderr stream, which will finally close the program with the code stating the exit has been failed.
Purposes
When it comes to the purposes, both the header files help the user achieve unique goals.
In short, stdio.h helps the coders to specify the input/output values and get the outcome. On the other hand, stdlib.h helps the coders to add necessary functions like the termination of the program inside the code.
Apart from these goals, here are other purposes served by these two header files.
Stdio.h
The main purpose of stdio.h is to make the computer allocate the input/output texts exactly at the place where the user wants it. If this header file isn’t added, the compiler will not run the code and it will cause an error. When stdio.h is added, the preprocessor of the compiler will take the desired program from the file.
Let’s say you’ve added the input and output values. Now how will the compiler understand that it must locate those values, run the program over it and give the outcome? It can certainly do that only if we include stdio.h which will navigate the compiler to dig the values from the file.
Stdlib.h
The main purpose of stdlib.h is to help the coder add the pre-existing functions related to memory allocation and freeing rather than having to create them. The other important purpose it serves is the deletion of the memory that gets used by the code. Often space complexity becomes a problem in coding but thanks to stdlib.h, coders can use the exit function which will automatically call the “destructor” to clear the space used.
Conclusion
Many programmers use C language because it’s high quality and boosts speed. We hope you enjoyed learning about the C language and about its library functions. Do practise this language with the help of online C compilers to perform well at interviews and increase your coding skills. We wish you the best in your coding endeavor.
