C - Introduction Comments



/*Displaying a Quotation */
#include <stdio.h>

int main(void)
  printf("hi from book2s.com!");
  return 0;

Look at the first line of code in the preceding example:

/*Displaying a Quotation */

This isn't actually part of the program code.

It's simply a comment, and it's there to remind you, or someone else reading your code, what the program does.

Anything between /* and */ is treated as a comment.

This may be on the same line or it can be several lines further on.

Here's how you could use a single comment to identify the author of the code and to assert your copyright:

 * Written by book2s.com
 * Copyright 2019

You can also embellish comments to make them stand out:

 * This is a very important comment        *
 * so please read this.                    *

You can add a comment at the end of a line of code using a different notation, like this:

printf("hi from book2s.com!");        // This line displays a quotation

Everything following two forward slashes on a line is ignored by the compiler. 

Let's add some more comments to the program:

/* Displaying a Quotation */
#include <stdio.h>                          // This is a preprocessor directive

int main(void)                              // This identifies the function main()
{                                           // This marks the beginning of main()
  printf("hi from book2s.com!");      // This line outputs a quotation
  return 0;                                 // This returns control to the operating system
}                                           // This marks the end of main()