% Fichier ex12.3.3-7.tex - Ch. Rolland/O Reilly France
\documentclass{article}
\usepackage[latin1]{inputenc}
\usepackage{fancybox}
\begin{document}
\newcounter{VerbLineNo}
\newenvironment{NVerbatim}{%
\VerbatimEnvironment
\renewcommand{\EveryVerbatimLine}%
{\makebox[10pt][r]{%
\stepcounter{VerbLineNo}%
\tiny\textrm{\arabic{VerbLineNo}}}%
\hspace{10pt}}
\renewcommand{\EveryVerbatim}%
{\setcounter{VerbLineNo}{0}}
\begin{Sbox}\begin{BVerbatim}}%
{\end{BVerbatim}\end{Sbox}
\begin{center}
\fbox{\TheSbox}\end{center}}
\begin{NVerbatim}
int i;
main()
{
  for(i=32;i<256;i++)
    printf("%d %c\t",i,i);
}
\end{NVerbatim}
\end{document}
