Menu
×
   ❮   
HTML CSS JAVASCRIPT SQL PYTHON JAVA PHP HOW TO W3.CSS C C++ C# BOOTSTRAP REACT MYSQL JQUERY EXCEL XML DJANGO NUMPY PANDAS NODEJS R TYPESCRIPT ANGULAR GIT POSTGRESQL MONGODB ASP AI GO KOTLIN SASS VUE DSA GEN AI SCIPY AWS CYBERSECURITY DATA SCIENCE
     ❯   

C Syntax


Syntax

You have already seen the following code a couple of times in the first chapters. Let's break it down to understand it better:

Example

#include <stdio.h>

int main() {
  printf("Hello World!");
  return 0;
}
Try it Yourself »

Example explained

Line 1: #include <stdio.h> is a header file library that lets us work with input and output functions, such as printf() (used in line 4). Header files add functionality to C programs.

Don't worry if you don't understand how  #include <stdio.h> works. Just think of it as something that (almost) always appears in your program.

Line 2: A blank line. C ignores white space. But we use it to make the code more readable.

Line 3: Another thing that always appear in a C program is main(). This is called a function. Any code inside its curly brackets {} will be executed.

Line 4: printf() is a function used to output/print text to the screen. In our example, it will output "Hello World!".

Note that: Every C statement ends with a semicolon ;

Note: The body of int main() could also been written as:
int main(){printf("Hello World!");return 0;}

Remember: The compiler ignores white spaces. However, multiple lines makes the code more readable.

Line 5: return 0 ends the main() function.

Line 6: Do not forget to add the closing curly bracket } to actually end the main function.


C Exercises

Test Yourself With Exercises

Exercise:

Insert the missing part of the code below to output "Hello World!":

int () {
 ("Hello World!");
  return 0;
}

Start the Exercise



×

Contact Sales

If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail:
[email protected]

Report Error

If you want to report an error, or if you want to make a suggestion, send us an e-mail:
[email protected]

W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using W3Schools, you agree to have read and accepted our terms of use, cookie and privacy policy.

Copyright 1999-2024 by Refsnes Data. All Rights Reserved. W3Schools is Powered by W3.CSS.