Talk:Dc (computer program)

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I have been unable to find any libraries of functions for 'dc' (e.g., log, sin, etc). If someone finds some, please add external links.

Wouldn't it be better to use an example that actually works? Because when I type
12 3 4 ^ + _11 / v 22 -
I get
dc: square root of negative number


Can someone explain how the following works?

It encodes the email address in the hex constant n=0x572CCB9AE9DB03273 and operates on it with the macro b defined as [ln0=aln80~Psnlbx]. This recursively calls itself until n is equal to zero. -- Autopilot (talk) 22:44, 15 May 2010 (UTC)
Just did a small optimization (in code length) to it: [q]sa[d0=a80~anlbx]16isb572CCB9AE9DB03273lbxq. Could anyone help writing another dc code to generate that hexadecimal number? I think it will be a good idea to add them, in pair, as an example of string handling in dc which is not yet covered by other examples. Billyauhk (talk) 08:08, 26 July 2011 (UTC)
 : Sorry but I forgotten that we cannot construct a string in dc...but I have just figured out the way to construct the constant: (echo -n "0123456789" | xxd -p -u -c 1; echo 0) | dc -"16i0[80?d0!=x*+]dsxx10op" (for Bash...and using GNU dc where != is accepted). For the string "Wikipedia", the constant is: 30E9C997869D7A6B80 Billyauhk (talk) 10:51, 26 July 2011 (UTC)

Original implementation language?[edit]

The current text says:

"It is one of the oldest Unix utilities, predating even the invention of the C programming language"

I believe that this is slightly incomplete. Wouldn't it be better to specify the original implementation language, rather than giving a hint at which one it is not? --Blazar.writeto() 14:39, 2 August 2008 (UTC)

A dc prototype for PDP-7 Unix was written in B. [1][2] Dc was written in assembly in V6. [3] It was rewritten in C for V7. [4] The Plan 9 version is essentially the same as the V7 version with a few small changes to accommodate the new C compiler. (talk) 06:27, 27 March 2011 (UTC)


There is a typo (or rather, a grammar mistake) in the article's "Input/Output" section: It says "... will affect the parsing of the every numeric value ..."—in my opinion, the second "the" is wrong, but I cannot change it myself as the article is protected. Would some registered user correct this, please?-- (talk) 14:33, 29 September 2011 (UTC)

Oops, obviously, it is not protected. I'm gonna change it myself. Cheers!-- (talk) 14:34, 29 September 2011 (UTC)


A commented version is slightly easier to understand ...

This example, Perl source containing embedded dc source, was formatted with language-specific, syntax-aware color coding. While I personally find that the jarring color shifts make source code almost unreadable, I would have left this style in place were it not already meaningless:

  1. The Wikipedia renderer doesn't have a style for “dc” source at all.
  2. The renderer doesn't handle nested source.
  3. The renderer doesn't handle multiple languages in one block of code.
  4. All the dc source, which (in this article on dc) is the whole point of the example, was rendered in one uniform color as being a single Perl function argument.

Since the colors only distracted from the dc example by highlighting the Perl code, I'm dropping those colors, leaving the dc and Perl source unchanged. (talk) 16:50, 19 April 2013 (UTC)

Some more examples of bad coloring needed attention. Editors, in this article about dc, it isn't clearly an improvement to try to color-code dc source using the Perl style, or the bash style, or any other unrelated style. (talk) 23:54, 24 April 2014 (UTC)