Comment (computer programming): Difference between revisions

Revision as of 21:22, 13 February 2025

Latest revision as of 19:33, 26 July 2025

(8 intermediate revisions by 5 users not shown)

Line 1:

{{Short description|Text in computer source code that is generally ignored by a compiler/interpreter}}

{{for|comments in Wikipedia markup|Help:Wiki markup#Character formatting|WP:COMMENT|selfref=yes}}

Missbah-Ul-Haq Khan Niazi - People In The World Never Love To Share Their Knowledge On Just About Anything & Everything. This Is The Truth. Comments In Computer Programming Are All Read & Understood In Technology, However, You Have To Understand That It Is Always One Thing When Computing Your Way To Success. Comments Help You Get Rid Of Errors In & On Any Level Of Computer Science You Are Studying Or Working At. This Is All I Know So Far. Bye. {{for|comments in Wikipedia markup|Help:Wiki markup#Character formatting|WP:COMMENT|selfref=yes}}

{{redirect2|/*|*/|their use in Wikipedia edit summaries|Help:Edit summary#Section editing|selfref=yes}}

[[File:CodeCmmt002.svg|thumb|right|300px|[[Java (programming language)|Java]] source code with block comments in <span style="color:#f00;">red</span>, line comments in <span style="color:#0e850e;">green</span> and program code in <span style="color:#00f;"> blue</span>.]]

Line 145:

| publisher=Cambridge University Press

| isbn=978-1-397-80521-8

}}</ref> Examples include [[Javadoc]], [[Ddoc]], [[Doxygen]], [[Visual Expert]] and [[PHPDoc]]. Forms of [[docstring]] are supported by [[Python (programming language)|Python]], [[Lisp (programming language)|Lisp]], [[Elixir (programming language)|Elixir]], and [[Clojure]].<ref>[https://clojure.github.io/clojure/clojure.core-api.html#clojure.core/defn Function definition with docstring in Clojure]</ref> [[C Sharp (programming language)|C#]], [[F Sharp (programming language)|F#]] and [[Visual Basic .NET]] implement a similar feature called "XML Comments" which are read by [[IntelliSense]] from the compiled [[.NET]] assembly.<ref>{{cite book|last=Murach|title=C# 2005|page=56}}</ref>

=== Visualization ===

Line 193:

=== Extend language syntax ===

Occasionally, code that is formatted as a comment is overloaded to convey additional information to the translator, such as [[conditional comment]]scomments. As such, syntax that generally indicates a comment can actually represent program code; not comment code. Such syntax may be a practical way to maintain compatibility while adding additional functionality, but some regard such a solution as a [[kludge]].<ref>[[c2: HotComments]]</ref>

Other examples include interpreter [[Directive (programming)|directives]]:

Line 292:

<syntaxhighlight lang="c">

/***************************\**

* *

* This is the comment body. *

* *

\ *****************************/

</syntaxhighlight>

Line 574:

====APL====

[[APL (programming language)|APL]] uses <code>⍝</code> ("lamp") for a line comment. For example:

<syntaxhighlight lang="apl">

Line 645:

====Fortran====

The following fixed-form [[Fortran IV]] code fragment shows that comment syntax is column-oriented. A letter <code>C</code> in the first column causes the entire line to be treated as a comment. In [[Fortran 77]], an asterisk in column 1 also indicates a comment.

<syntaxhighlight lang="fortranfixed">

Line 660:

<syntaxhighlight lang="Fortran">

! A comment

program comment_test

print '(A)', 'Hello world' ! also a comment

end program

</syntaxhighlight>

Free-form Fortran, also introduced with Fortran 90, only supports this latter style of comment.

Although not a part of the Fortran Standard, many Fortran compilers offer an optional C-like [[preprocessor]] pass. This can be used to provide block comments:

<syntaxhighlight lang="Fortran">

#if 0

This is a block comment spanning

multiple lines.

#endif

program comment_test

print '(A)', 'Hello world' ! also a comment