General ⇒ Issues with trying to hyperref Exercises and Solutions

[awegawef]

Hey, I'm trying to use the hyperref package to link Exercises to Solution (and maybe hints) and vice versa. IE:

Exercise 1. Do this (Link to Hint) (Link to Solution)

and then the solutions page would have

Solution 1. This is the solution. (Link to Original Problem)

The code that I tried to throw together is as follows

Code: Select all

\theoremstyle{definition}
\newtheorem{exer}{Exercise}
\newtheorem{sol}{Solution}

\newcounter{exercises}
\newcounter{solutions}
\setcounter{exercises}{0}
\setcounter{solutions}{0}

\newcommand{\ex}{ %to start an exercise
	\begin{exer}
		\hypertarget{\value{exercises}-exer}{}
	}
\newcommand{\eex}{ % to end an exercise
		\hyperlink{\value{exercises}-sol}{Solution}
	\end{exer}
	\addtocounter{exercises}{1}
	}
\newcommand{\so}{ % start a solution
	\begin{sol}
		\hypertarget{\value{solutions}-sol}{}
	}
\newcommand{\eso}{ % end a solution
		\hyperlink{\value{solutions}-exer}{Exercise}
	\end{sol}
	\addtocounter{solutions}{1}
	}

What I tried to do was create my own counter, but what happens is that \value{exercises} and \value{solutions} are always printed out as nothing. Does anyone know how to fix this? I've researched but I haven't been able to figure out counters. I'm sure there is a better way to do this, too, so if anyone has input on that, please let me know.

Thanks.

[frabjous]

I think it should work if you use \theexercises and \thesolutions instead of \value{solution} or \value{exercises}.

Also, I'd start your counters at 1, not 0, unless you want them not to match their labels.

E.g.:

Code: Select all

\documentclass{article}
\usepackage{amsthm}
\usepackage{hyperref}
\theoremstyle{definition}
\newtheorem{exer}{Exercise}
\newtheorem{sol}{Solution}

\newcounter{exercises}
\newcounter{solutions}
\setcounter{exercises}{1}
\setcounter{solutions}{1}

\newcommand{\ex}{ %to start an exercise
   \begin{exer}
      \hypertarget{\theexercises-exer}{}
   }
\newcommand{\eex}{ % to end an exercise
      \hyperlink{\theexercises-sol}{Solution}
   \end{exer}
   \addtocounter{exercises}{1}
   }
\newcommand{\so}{ % start a solution
   \begin{sol}
      \hypertarget{\thesolutions-sol}{}
   }
\newcommand{\eso}{ % end a solution
      \hyperlink{\thesolutions-exer}{Exercise}
   \end{sol}
   \addtocounter{solutions}{1}
   }
\begin{document}
\ex
This is exercise \theexercises.
\eex
\clearpage
\ex
This is exercise \theexercises.
\eex
\clearpage
\so
This is solution \thesolutions.
\eso 
\clearpage
\so
This is solution \thesolutions.
\eso 

\end{document}

[awegawef]

Thanks for the reply! Your method works great. I wasn't worried about the counters matching the labels because the labels are going to be specific to the subsections, ie Ex 2.1.1, Ex 2.1.2, etc. I don't think it really matters how the link numbers are chosen as long as the solutions appear sequentially at the end, which they will of course.

Once again, thanks for the help!

[sitex]

I am happy that the strategy posted by frabjous worked for you. If you are interested in a completely automated solution (one that automatically generates cross-references, etc) you can look at Don Story's exerquiz package which is a part of his AcroTeX eDucation Bundle (http://www.math.uakron.edu/~dpstory/webeq.html). I began using this free package when Don wrote it. It is easy to implement and provides for considerable flexibility. Your input is simply
<

Code: Select all

\begin{exercise}
  <statement of the exercise>
\begin{solution}
  <exercise solution>
\end{solution}
\end{exercise}

The rest is done by exerquiz. Options permit you to place some or all solutions after the exercises, at the end of the document, or omit the solutions entirely (in which case you can leave space for the student to work the problem). I have used eCard package to include hints.

Tom