Preformatted

Use the Preformatted tag for computer code:

\long\def\@caption#1[#2]#3{%
  \par
   %\edef\@tempa{\csname #1TOCLabel\endcsname}
   \AddContentsLine
   {\csname ext@#1\endcsname}%
   {#1@toc}%
   {\csname #1toclabel\endcsname}%
   {\ignorespaces #2}%
   \begingroup
     \@parboxrestore
     \normalsize
     \csname @makecaption#1\endcsname{\ignorespaces #3}\par
   \endgroup}