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(computer science)
An expression identifying or explaining one or more steps in a routine, which has no effect on execution of the routine.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


(Or "remark") Explanatory text embedded in program source (or less often data) intended to help human readers understand it.

Code completely without comments is often hard to read, but code with too many comments is also bad, especially if the comments are not kept up-to-date with changes to the code. Too much commenting may mean that the code is over-complicated. A good rule is to comment everything that needs it but write code that doesn't need much of it. Comments that explain __why__ something is done and how the code relates to its environment are useful.

A particularly irksome form of over-commenting explains exactly what each statement does, even when it is obvious to any reasonably competant programmer, e.g.

/* Open the input file */ infd = open(input_file, O_RDONLY);
This article is provided by FOLDOC - Free Online Dictionary of Computing (


Lines of documentation in program source code and batch file scripts. Comments, also called "remarks," are words or symbols that identify a line or a group of lines as text that is not to be compiled or executed.

Comment Quality
The bottom line is that most programmers hate to document, and the quality of the documentation ranges from the ridiculous to the sublime (rarely sublime). The quality of the comments goes a long way in determining the ease with which a program can be changed, not only by other programmers, but also by the original programmer. See obfuscator and comment out.

Sample Codes for Comments/Remarks
When several lines of comments are used, the start and stop symbols for multi-line comments eliminate having to enter a code on each line.
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References in classic literature ?
"That Beecher certainly was slick," commented Professor Bumper when they were ready to start.
"Which," Powell again commented to me earnestly, "was a lie .
"That was nearly thirty years ago," commented his wife crisply, "and Rose's got so used to being bossed around by Martin that she'll find it ain't so easy to go ahead on her own."
So they say "no comment" or refuse to pick up calls or messages as a way of refusing to answer a journalist's questions.However, the "no comment" or refusal to talk to a journalist is a comment in itself, though the person may wish to say nothing.
Consider the following cases:Journalist: Governor, how long have you been paying suppliers for goods not delivered?Governor: No comment.Journalist: Do you approve the caning of students?Headmaster: I've nothing to say on this matter.
names take the power of the opportunity to comment on agency rulemakings
parties with opportunity to comment on proposed rules (7) and then
In the past, a note or comment appeared as a small yellow rectangle that resembled a Post-it Note.
The Comment tools on the Review tab of the Ribbon apply to the new threaded comments.
"This year's comment volume dwarfed that and our analysis highlights the relative ease with which online commenting systems allow groups and individuals to mount large-scale campaigns for public policies.
The comment process for net neutrality has been the cause of significant controversy over the course of the net neutrality debate.
Reader: Despite the R-G's good intentions, Civil Comments is a very poor attempt at a solution.