Algorithm2e package of LaTeX

\usepackage[ruled,vlined]{algorithm2e}

\begin{algorithm}
 \SetAlgoLined
 \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}

References

1. http://www.tex.ac.uk/tex-archive/macros/latex/contrib/algorithm2e/algorithm2e.pdf
2. Algorithms in Latex