# What are comments in programming languages?

**Comments** in programming languages are used to document the programs. Comments are non-executable and are used to explain the code written in the program. 

Different programming languages have different syntaxes for writing the comments in the program. Let's have a look at a few of them.

## Comments in C++, Javascript, JAVA, and PHP

There are two ways to comment in C+, Javascript, JAVA, and PHP:

* Single-line comments  `//` 
* Multi-line comments `/*` 

In single-line commenting, the text starting with `//` to the end of the line is ignored by the compiler and not executed.      
  In multiline commenting, the code between `/*` and `*/` is considered as comments and not executed. 




#include <iostream>
using namespace std;

int main() {
  // This is the comment and is ignored by the compiler.
  cout << "This line is executed by the compiler." << endl;
  /*
    this 
    is 
    multiline 
    comment
  */
  cout << "After the comments this code is executed.";
  return 0;
}

class HelloWorld {
    public static void main( String args[] ) {
      // This is the comment and is ignored by the compiler.
      System.out.println( "This line is executed by the compiler." );
      /*
        this 
        is 
        multiline 
        comment
      */
      System.out.println( "After the comments this code is executed." );
    }
}

Java

// This is the comment and is ignored by the compiler.
console.log( "This line is executed by the compiler." );
/*
    this 
    is 
    multiline 
    comment
*/
console.log( "After the comments this code is executed." );

Javascript

<?php 
    // This is the comment and is ignored by the compiler.
    echo "This line is executed by the compiler. \n";
    /*
        this 
        is 
        multiline 
        comment
    */
    echo "After the comments this code is executed.";
?>

## Comments in Python, Ruby, and R


There are two ways to comment in Python, Ruby, and R:

* Single-line comments  `#` 
* Multi-line comments  

### Single-line comments



print "Hello World"
# this is single line comments

Python

puts "Hello World!"
# this is single line comments

Ruby

cat("Hello world")
# this is single line comments

### Multi-line comments

> **Note:** R does not support multi-line comments.

Multi-line comments for Python and Ruby are given below:


print "Hello World"
"""
    this is the 
    way to write 
    multiline comment in python
"""

puts "Hello World!"
=begin
    this is the 
    multiline comments
=end


How to comment in different programming languages

Comments in programming are used for documentation and vary by language. They can be single-line or multi-line.