%%
%% The LaTeX Companion, 3ed
%%
%% Example 4-2-60 on page I-332 in "listings --- Pretty-printing program code".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{159.0pt}

%StartShownPreambleCommands
\usepackage{xcolor,listings}
\lstset{literate={:=}{{$\gets$}}{2} {<=}{{$\leq$}}{1}
                 {>=}{{$\geq$}}{1}  {<>}{{$\neq$}}{1}}
%StopShownPreambleCommands

\begin{document}
\begin{lstlisting}[backgroundcolor=\color{yellow}]
  var i:integer;
  if (i<>0) i := i/2;
  if (i<=0) i := i+1;
  if (i>=0) i := i-1;
\end{lstlisting}
\end{document}
