%%
%% The LaTeX Companion, 3ed
%%
%% Example A-2-8 on page II-654 in "Horizontal space".
%%
%% 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{183.0pt}
%StartShownPreambleCommands

%StopShownPreambleCommands

\begin{document}
\newcommand{\HS}[1][1.]{\hspace{\stretch{#1}}}
\begin{center}
left \hfill                            right\\
left \HS[2]\fbox{$\frac{2}{5}$}\HS[5]  right\\
left \HS         middle \hfill         right\\
left \hrulefill\ middle \hrulefill\    right\\
left \dotfill\                         right\\
left \dotfill\ \HS[.5] \dotfill\       right\\
left \dotfill\ \HS     \dotfill\       right\\
left \dotfill\ \HS[2.] \dotfill\       right
\end{center}
\end{document}