%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 5-7-7 on page 276.
%%
%% 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{207.0pt}
\StartShownPreambleCommands
\usepackage{dcolumn}
\StopShownPreambleCommands
\begin{document}
\begin{tabular}{|D..{-1}|D..{2}|D..{4.2}|}
\multicolumn{1}{|c|}{wide heading}&
\multicolumn{1}{c|}{wide heading}&
\multicolumn{1}{c|}{wide heading}\\[3pt]
 1000.20  & 1000.20  &1000.20 \\
 123.45    & 123.45    & 123.45
\end{tabular}
\end{document}