• Fortran

! This is a comment.

• VB

Rem this is a comment line

• Ada

-- This is a comment

• C

// This is a comment.

• Clojure

;This is a comment.

;;This is a comment.

;;;This is a comment.

• C++

// This is a comment.

• C#

// This is a comment

• Dart

// This is a comment

• Go

// This is a comment

• Haskell

-- This is a comment

• JS

// This is a comment

• Java

// This is a comment

• Lisp

;; comment

• Lua

-- This is a comment

• Pascal

// a line of comments, this line will not be compiled or executed.

• Perl

# This is a comment

• Python

# This is a comment

• Ruby

# This is a comment

• Rust

// This is a comment