Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

I will to align comments in another column, package algorithm. (Similar question: Faulty right alignment for comments in algorithmic package), but I will to become that result:

enter image description here

\usepackage{algorithm,algorithmic}
\renewcommand{\algorithmiccomment}[1]{\bgroup\hfill//~#1\egroup}

[...]

\begin{algorithm}
\caption{$function(n : \mathbb{N}_0) : \mathbb{N}_0$}
\label{algo1}
\begin{algorithmic}[1]
   \REQUIRE $n \in \mathbb{N}_0$
   \STATE $result \leftarrow 0 : \mathbb{N}_0$
   \STATE $temp \leftarrow 1 : \mathbb{N}_0$
   \FOR[$n$ Durchläufe]{$i \leftarrow 0$ \TO $n-1$}
     \FOR{$j \leftarrow i$ \TO $i$}
       \STATE $temp \leftarrow temp \cdot 2$ \COMMENT{Multiplikation}
     \ENDFOR
     \STATE $result \leftarrow result + temp$ \COMMENT{Addition}
     \STATE $temp \leftarrow 1$
   \ENDFOR
   \RETURN $result$
\end{algorithmic}
\end{algorithm}
share|improve this question
2  
Please always supply a complete (\documentclass to \end{document}) example document that demonstrates the problem and allows people to test their answers. –  David Carlisle May 24 at 22:19

1 Answer 1

up vote 7 down vote accepted

Here is an algorithmicx implementation:

enter image description here

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{algorithm,algcompatible,amssymb,amsmath}
\renewcommand{\COMMENT}[2][.5\linewidth]{%
  \leavevmode\hfill\makebox[#1][l]{//~#2}}
\algnewcommand\algorithmicto{\textbf{to}}
\algnewcommand\RETURN{\State \textbf{return} }
\begin{document}

\begin{algorithm}
  \caption{$\text{function}(n : \mathbb{N}_0) : \mathbb{N}_0$}\label{algo1}
  \begin{algorithmic}[1]
    \REQUIRE $n \in \mathbb{N}_0$
    \STATE $\text{result} \leftarrow 0 : \mathbb{N}_0$
    \STATE $\text{temp} \leftarrow 1 : \mathbb{N}_0$
    \FOR{$i \leftarrow 0$ \algorithmicto{} $n-1$} \COMMENT{$n$ Durchläufe}
      \FOR{$j \leftarrow i$ \algorithmicto{} $i$}
        \STATE $\text{temp} \leftarrow \text{temp} \cdot 2$ \COMMENT{Multiplikation}
      \ENDFOR
      \STATE $\text{result} \leftarrow \text{result} + \text{temp}$ \COMMENT{Addition}
      \STATE $\text{temp} \leftarrow 1$
    \ENDFOR
    \RETURN $\text{result}$
  \end{algorithmic}
\end{algorithm}
\end{document}

\COMMENT[<len>]{<stuff>} is reformatted to put the comment <stuff> in a box of width <len> (default is .5\linewidth) flush right. You can adjust this to your liking.


A pure algorithmic implementation is somewhat different:

\usepackage{letltxmacro}

\newlength{\commentindent}
\setlength{\commentindent}{.5\textwidth}
\makeatletter
\renewcommand{\algorithmiccomment}[1]{\unskip\hfill\makebox[\commentindent][l]{//~#1}\par}
\LetLtxMacro{\oldalgorithmic}{\algorithmic}
\renewcommand{\algorithmic}[1][0]{%
  \oldalgorithmic[#1]%
  \renewcommand{\ALC@com}[1]{%
    \ifnum\pdfstrcmp{##1}{default}=0\else\algorithmiccomment{##1}\fi}%
}
\makeatother

It uses e-TeX (for the string comparison), but that can be changed. The reason for the difference in implementation is mainly because of the way loops are handled in algorithmic - the comment is inserted as an optional argument to the loop structure. As such, it's difficult to allow another optional argument for the length parameter as above in the algorithmicx implementation. The work-around is to define a length \commentindent that handles this in a similar way the optional argument would handle things.

Here's a full implementation, with the same output:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{algorithm,algorithmic,amssymb,amsmath,letltxmacro}
\newlength{\commentindent}
\setlength{\commentindent}{.5\textwidth}
\makeatletter
\renewcommand{\algorithmiccomment}[1]{\unskip\hfill\makebox[\commentindent][l]{//~#1}\par}
\LetLtxMacro{\oldalgorithmic}{\algorithmic}
\renewcommand{\algorithmic}[1][0]{%
  \oldalgorithmic[#1]%
  \renewcommand{\ALC@com}[1]{%
    \ifnum\pdfstrcmp{##1}{default}=0\else\algorithmiccomment{##1}\fi}%
}
\makeatother

\begin{document}

\begin{algorithm}
  \caption{$\text{function}(n : \mathbb{N}_0) : \mathbb{N}_0$}\label{algo1}
  \begin{algorithmic}[1]
    \REQUIRE $n \in \mathbb{N}_0$
    \STATE $\text{result} \leftarrow 0 : \mathbb{N}_0$
    \STATE $\text{temp} \leftarrow 1 : \mathbb{N}_0$
    \FOR[$n$ Durchläufe]{$i \leftarrow 0$ \TO $n-1$}
      \FOR{$j \leftarrow i$ \TO $i$}
        \STATE $\text{temp} \leftarrow \text{temp} \cdot 2$ \COMMENT{Multiplikation}
      \ENDFOR
      \STATE $\text{result} \leftarrow \text{result} + \text{temp}$ \COMMENT{Addition}
      \STATE $\text{temp} \leftarrow 1$
    \ENDFOR
    \RETURN $\text{result}$
  \end{algorithmic}
\end{algorithm}
\end{document}
share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.