# Code listings in LaTeX

‘Pretty’ code listings are sometimes considered worthwhile by the “ordinary” programmer, but they have a serious place in the typesetting of dissertations by computer science and other students who are expected to write programs. Simple verbatim listings of programs are commonly useful, as well.

Verbatim listings are dealt with elsewhere, as is the problem of typesetting algorithm specifications.

The listings package is widely regarded as the best bet for formatted output (it is capable of parsing program source, within the package itself), but there are several well-established packages that rely on a pre-compiler of some sort. You may use listings to typeset snippets that you include within your source:

\usepackage{listings}
\lstset{language=C}
...
\begin{document}
\begin{lstlisting}
#include

int main(int argc, char ** argv)
{
printf("Hello world!\n");
return 0;
}
\end{lstlisting}
\end{document}

or you can have it typeset whole files:
\usepackage{listings}
\lstset{language=C}
...
\begin{document}
\lstinputlisting{main.c}
\end{document}

These very simple examples may be decorated in a huge variety of ways, and of course there are other languages in the package’s vocabulary than just C

For a long time, advice on (La)TeX lists seemed to regard listings as the be-all and end-all on this topic. In the last few years, viable alternatives have appeared

Highlight is attractive if you need more than one output format for your program: as well as (La)TeX output, highlight will produce (X)HTML, RTF and XSL-FO representations of your program listing. The manual leads you through the details of defining a parameter file for a “new” language, as well as the presentation details of a language.

The minted package is another alternative that offers the means of creating new language definitions. It requires that code be processed using an external (python) script, Pygments. Pygments, in turn, needs a “lexer” that knows the language you want to process; lots of these are available, for the more commonly-used languages, and there is advice on “rolling your own” on the Pygments site

Usage of minted can be as simple as

\begin{minted}{‹language›}

\end{minted}
which processes the program code dynamically, at typesetting time — though such usage is likely to require that separate processing be enabled.

On a rather different path, the package showexpl supports typesetting (La)TeX code and its typeset output, in parallel ‘panes’. (Thiscould provide support for (La)TeX instruction texts, or for papers in TeX user group publications. The package uses listings for its (La)TeX pane, and typesets the result into a simple box, for the other pane.

Longer-established, and variously less “powerful” systems include:

• The lgrind system is a well-established pre-compiler, with all the facilities one might need and a wide repertoire of languages; it is derived from the even longer-established tgrind, whose output is based on Plain TeX.
• The tiny_c2l system is slightly more recent: users are again encouraged to generate their own driver files for languages it doesn’t already deal with, but its “tiny” name correctly hints that it’s not a particularly elaborate system.
• The C++2LaTeX system comes with strong recommendations for use with C and C++.
• An extremely simple system is c2latex, for which you write LaTeX source in your C program comments. The program then converts your program into a LaTeX document for processing. The program (implicitly) claims to be “self-documenting”.
c2latex
c2latex
C++2LaTeX
c++2latex
highlight
highlight
lgrind
lgrind
listings.sty
listings
minted.sty
minted
showexpl.sty
showexpl
tgrind
tgrind
tiny_c2l
tiny_c2l