The example for the code is from the manual (v.4.01). Following the example at Latex-algorithmic-if-else.png, this was produced by the following:

$ cat algorithm2e.tex          
\documentclass[12pt]{article}                                           
\usepackage[lined,boxed,commentsnumbered]{algorithm2e}
\usepackage[right=5cm]{geometry}                                        
\usepackage[active,pdftex,tightpage]{preview}                           
\PreviewEnvironment[]{algorithm}                                      
\begin{document}

\begin{algorithm}[H]
 \SetAlgoLined % new in release 4.01 (Dec 2009); doesn't work in release 3.9 (Oct 2005)
 \KwData{this text}
 \KwResult{how to write algorithm with \LaTeX2e }
 initialization\;
 \While{not at end of this document}{
  read current\;
  \eIf{understand}{
  go to next section\;
  current section becomes this one\;
  }{
  go back to the beginning of current section\;
  }
 }
 \caption{How to write algorithms}
\end{algorithm}

\end{document}

$ # Download the package:
$ wget http://www.tex.ac.uk/tex-archive/macros/latex/contrib/algorithm2e/algorithm2e.sty                                        
$ # Compile latex:
$ pdflatex algorithm2e.tex
...
$ pdftoppm -r 600 algorithm2e.pdf algorithm
$ convert algorithm-1.ppm latex-algorithmic2e-if-else.png

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