%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 5-9-2 on page 280.
%%
%% Copyright (C) 2004 Frank Mittelbach, Michel Goossens,
%%    Johannes Braams, David Carlisle, and Chris Rowley
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%%
%% See http://www.latex-project.org/lppl.txt for details.
%%

\documentclass{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{159.0pt}
\StartShownPreambleCommands
\usepackage{array}
\newlength\Mylen
\StopShownPreambleCommands
\begin{document}
\settowidth\Mylen{this-is-a-rather-long-row}
\addtolength\Mylen{2\tabcolsep}
\begin{tabular*}{\Mylen}%
         {!{\extracolsep{4in minus 4in}}ccc}
\multicolumn{3}{c}{this-is-a-rather-long-row}\\
C1 &C2 &C3 \\ 2.1&2.2&2.3 \\ 3.1&3.2&3.3
\end{tabular*}
\end{document}