How display LaTeX code in LaTeX document?

Question

I'm making Beamer presentation. How I can display LaTeX code inside presentation?

Answer 1

Either simply within the verbatim environment or more sophisticated with the listings package.

Answer 2

If you want the input LaTeX codes displayed together with their corresponding outputs side by side (left/right or top/bottom), use showexpl.sty. It is a really cool package.

There are 2 modes:

1. the input code is inserted into your document, or
2. the input code is imported from external file.

EDIT 1:

The following figure shows showexpl.sty in action:

And the corresponding code is given as follows: Note: I gave some comments in the code to make it clearer.

\documentclass[final,dvipsnames]{article}
\usepackage[hmargin=70mm]{geometry}
\usepackage{xcolor}
\usepackage{bera}
\usepackage{pstricks-add}

\usepackage{caption}
\captionsetup{%
   margin=0em,
   font={scriptsize,rm},
   labelfont={color=Maroon,bf},
   justification=justified,%default: RaggedRight. Other options: justified, centering
   labelsep=quad%default:colon. Options: period, space, quad, newline
}
\usepackage{showexpl}
\usepackage{etoolbox}
\makeatletter
\patchcmd{\SX@codeInput}{xleftmargin=0pt,xrightmargin=0pt}{}
  {\typeout{***Successfully patched \protect\SX@codeInput***}}
  {\typeout{***ERROR! Failed to patch \protect\SX@codeInput***}}
\makeatother
\lstset{%
    breaklines=true,%default : false 
  breakindent=10pt,%default: 20pt 
    linewidth=\linewidth,%default : \linewidth,
    basicstyle=\ttfamily\tiny,% cannot take arguments
    keywordstyle=\color{Blue}\sffamily\bfseries,                                
    identifierstyle=\color{Black},                                      
    commentstyle=\color{OliveGreen}\itshape,                                    
    stringstyle=\rmfamily,                                                      
    showspaces=false,%default false
    showstringspaces=false,%default: true
    backgroundcolor=\color{Yellow!30},
    frame=single,%default frame=none 
    rulecolor=\color{Red},  
    % the following must be defined to make hacking work.
    framerule=0.4pt,%expand outward 
    framesep=3pt,%expand outward
    xleftmargin=3.4pt,%to make the frame fits in the text area. 
    xrightmargin=3.4pt,%to make the frame fits in the text area. 
    tabsize=2%,%default :8 only influence the lstlisting and lstinline.
}
\lstset{%
    %explpreset below will affect LTX only.
    explpreset={%
                            language={[LaTeX]TeX},
                            captionpos=t,
                            aboveskip=2\fboxsep,                        
                            pos=b,
                            vsep=\fboxsep%vertical space between formatted and input.
                         }%
}

\newcommand\mywidth{0.5\linewidth}


\newcommand\dummy{%
Thank you to those who never get tired of helping me.
Thank you to those who never get tired of helping me.
Thank you to those who never get tired of helping me.
Thank you to those who never get tired of helping me.
Thank you to those who never get tired of helping me.
}


\begin{document}
\begin{LTXexample}[caption=\dummy]
\dummy
\begin{enumerate}
\item $\displaystyle \lim_{x\to 8}\frac{1}{(x-8)^2}=+\;\rotatebox{90}{$8$}$
\item $\displaystyle \lim_{x\to 7}\frac{1}{(x-7)^2}=+\;\rotatebox{90}{$7$}$
\item $\displaystyle \lim_{x\to 6}\frac{1}{(x-6)^2}=+\;\rotatebox{90}{$6$}$
\end{enumerate}
\end{LTXexample}
\end{document}

Answer 3

How about to use verbatiminput? If you have the LaTeX examples in a file?

\usepackage{verbatim}
\verbatiminput{ my_test.tex }