%%
%% The LaTeX Companion, 3ed
%%
%% Example 7-3-3 on page I-531 in "float --- Creating new float types".
%%
%% 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}
\setcounter{page}{1}
\setlength\textheight{13.5\baselineskip}
\setlength\textfloatsep{12pt plus 4pt minus 4pt}
% for the book examples we shorten the
% vertical spaces and use a smaller font for
% the heading
\makeatletter
\renewcommand\section{\@startsection{section}{1}{\z@}%
                                    {-1.35ex \@plus-1ex \@minus-.2ex}%
                                    {.3ex}%
                                    {\normalfont\large\bfseries}}
\makeatother
\addtolength\textwidth{-10pt}      % account for boxed float sticking out into margin

%StartShownPreambleCommands
  \usepackage{lipsum,graphicx,float}
  \floatstyle{boxed} \restylefloat{figure}
  \floatstyle{ruled} \restylefloat{table}
  \floatplacement{table}{b}
%StopShownPreambleCommands

\begin{document}
  \section{Customizing standard floats}
  \lipsum[1][1]
  \begin{table}  \begin{tabular}{@{}llr}
    AA & BBB & 123\\ CCC & DDDD & 45\end{tabular}
   \caption{Sample table}
  \end{table}%
  \begin{figure} \centering
   \includegraphics[width=12mm]{rosette}
   \caption{Sample figure}
  \end{figure}
  \lipsum[1][2]
\end{document}