So let’s look at our first C program!

#include <stdio.h>

int main() {
  // output a line
  printf("Hello World!\n");
}

When this code is run the following text is displayed in the terminal.

Hello World!

Let’s go through the code line by line to see what is happening. You don’t need to understand everything right away, this is just a first look.

• #include <stdio.h>: This line is needed to run the line of code that starts with printf.
• int main(){ }: This is the starting point of the code. All the code inside the curly braces {} runs first.
• // output a line: This is a comment. It is not a line of code but a message we can add to code to tell ourselves or others what the code does. When the code is run this line will be ignored.
• printf("Hello World!");: This line of code prints, or outputs, the text “Hello World!” to the console. Printing text to the console is one way for a program to communicate with the user.

Try running the code and see the output yourself!