How to write Comments in C Programming

Details: Last Updated: 06 April 2021

What Is Comment In C Language?

A comment is an explanation or description of the source code of the program. It helps a developer explain logic of the code and improves program readability. At run-time, a comment is ignored by the compiler.

There are two types of comments in C:

1) A comment that starts with a slash asterisk /* and finishes with an asterisk slash */ and you can place it anywhere in your code, on the same line or several lines.

2) Single-line Comments which uses a double slash // dedicated to comment single lines

Example Single Line Comment

// single line comment example

Here is an example of comments type

// C program to demo 
// Single Line comment 
#include <stdio.h> 
int main(void) 
{ 
  
	// This is a single line comment 
	printf("Guru99"); 
	return 0;  // return zero
}

Example Multi Line Comment

/* Sample Multiline Comment
Line 1
Line 2
….
…
*/

Example Multi Line Comment

#include <stdio.h>
int main() {
/* in main function
I can write my principal code
And this in several comments line */
int x = 42; //x is a integer variable
printf("%d", x);
return 0;}

Why do you need comments?

A good programmer who writes codes understood by a human is better than a programmer who generates codes understood only by the machine.

So, it is highly recommended to insert comments to your code because it is good programming practice. Comments do not affect a program because the compiler ignores them.

Comments help the developer understand the logic/algorithm of the code if he revisits it after a long time.