Frequently Asked Question List for TeX
There is no consensus on the “right” way to typeset pseudocode. Consequently, there are a variety of LaTeX packages to choose from for producing æsthetically pleasing pseudocode listings.
Pseudocode differs from actual program listings in that it lacks strict syntax and semantics. Also, because pseudocode is supposed to be a clear expression of an algorithm it may need to incorporate mathematical notation, figures, tables, and other LaTeX features that do not appear in conventional programming languages. Typesetting program listings is described elsewhere.
You can certainly create your own environment for typesetting
pseudocode using, for example, the
list environments — it’s not difficult, but it may
prove boring. So it’s worth trying the following packages, all
designed specifically for typesetting pseudocode.
algorithms bundle (which contains packages
algorithmic, both of which are
needed for ordinary use) has a simple interface and produces fairly
nice output. It provides primitives for statements, which can contain
arbitrary LaTeX commands, comments, and a set of iterative and
conditional constructs. These primitives can easily be redefined to
produce different text in the output. However, there is no support
for adding new primitives. Typesetting the pseudocode itself is
uses the facilities of the
float package to number
algorithms sequentially, enable algorithms to float like figures or
tables, and support including a List of Algorithms in a document’s
Packages in the
algorithmicx bundle are similar both in
concept and output form to
algorithmic but additionally
provide support for adding new keywords and altering the formatting.
It provides the
algpseudocode package which is (almost) a
drop-in replacement for
algorithmic. Another package in the
algpascal, uses Pascal-like keywords, indents
algpseudocode, and puts command arguments
in maths mode instead of text mode. There is no floating environment
is compatible with the
(There have been reports of difficulty defining new commands to fit with the package;
unfortunately, the author is not available to comment.)
alg package, like
offers a floating algorithm environment with all of the ensuing niceties.
alg, however, can caption its floats in a variety of
(natural) languages. In addition,
algorithms, makes it easy to add new constructs.
newalg package has a somewhat similar interface to
algorithms, but its output is designed to mimic the rather
pleasant typesetting used in the book “Introduction to Algorithms”
by Cormen, Leiserson, Rivest and Stein. Unfortunately,
newalg does not support a floating environment or any
customisation of the output.
“Bona fide” use of the style of “Introduction to Algorithms” may be achieved
with Cormen’s own
this is the package as used in the second edition of the book.
Similarly, the style of “Combinatorial Algorithms: Generation, Enumeration and Search”
is supported by the
pseudocode package, written by the
authors of the book. It has the common “Pascal-like” style, and has
some interesting constructs for what one thinks of as Pascal blocks.
algorithm2e is of very long standing, and is widely used
and recommended. It loads the
float package to provide the
option of floating algorithm descriptions, but you can always use the
float to have the algorithm appear “where you write it”.
The usage of the
program package is a little different from
that of the other packages. It typesets programs in maths mode
instead of text mode; and linebreaks are significant.
program lacks a floating environment but does number
Customisation and extension are not supported. Documentation of the
program package is short, but a demo file,
program-demo.tex, is provided in the distribution and shows a lot more examples.
None of the above are perfect. The factors that should influence your choice of package include the output style you prefer, how much you need to extend or modify the set of keywords, and whether you require algorithms to float like figures and tables.
FAQ ID: Q-algorithms