# Referring to example numbers in tcolorbox

In a question I asked before, I implemented method 2 by feculededentier. However, now I am facing difficulty in referring to different examples in this case. For example, what should be the Latex code for "as shown in Example 1.2"?

You have to slightly change the definition. Make it 2 arguments with first one as optional:

\newtcolorbox[auto counter, number within=chapter, number freestyle={\noexpand\thechapter.\noexpand\arabic{\tcbcounter}}]{myexample}[2][]{%
enhanced,
breakable,
fonttitle=\bfseries,
title=Example~\thetcbcounter: #2,
#1
}


And then use the label=<name> key like

\begin{myexample}[label=second]{Second example}


Now you can use Example~\ref{second} to refer to these boxes.

Full example (taken and modified from the answer linked in the question)

\documentclass{book}
\usepackage{tcolorbox}
\tcbuselibrary{skins,breakable}
\usepackage{lipsum}

\newtcolorbox[auto counter, number within=chapter, number freestyle={\noexpand\thechapter.\noexpand\arabic{\tcbcounter}}]{myexample}[2][]{%
enhanced,
breakable,
fonttitle=\bfseries,
title=Example~\thetcbcounter: #2,
#1
}

\begin{document}

\chapter{First chapter}

\begin{myexample}[label=first]{First example}
\lipsum[4]
\end{myexample}

\begin{myexample}[label=second]{Second example}
\lipsum[4]
\end{myexample}

\chapter{Second chapter}

\begin{myexample}[label=third]{Third example}
\lipsum[4]
\end{myexample}

From Example~\ref{second} we get some idea.

\end{document}


# cleveref version:

You can load cleveref package and use crefname in the options to reduce typing.

\documentclass{book}
\usepackage{cleveref}
\usepackage{tcolorbox}
\tcbuselibrary{skins,breakable}
\usepackage{lipsum}

\newtcolorbox[auto counter, number within=chapter,
crefname={example}{examples},
Crefname={Example}{Examples},
number freestyle={\noexpand\thechapter.\noexpand\arabic{\tcbcounter}}]
{myexample}[2][]{%
enhanced,
breakable,
fonttitle=\bfseries,
title=Example~\thetcbcounter: #2,
#1
}

\begin{document}

\chapter{First chapter}

\begin{myexample}[label=first]{First example}
\lipsum[4]
\end{myexample}

\begin{myexample}[label=second]{Second example}
\lipsum[4]
\end{myexample}

\chapter{Second chapter}

\begin{myexample}[label=third]{Third example}
\lipsum[4]
\end{myexample}

\Cref{second} gives us some idea as seen from \cref{first}.

\end{document}

• Not working for me. Adding #2, #1 creates the problem. The error is missing number, treated as zero. – Qasim Chaudhari Aug 28 '15 at 6:02
• @QasimChaudhari Are you compiling the code as such without modifying? If you still get the error, please try updating your tcolorbox package. – user11232 Aug 28 '15 at 6:07
• Harish, it worked very well now. Thanks! Actually I had a \vspace{2mm} immediately after starting the box, and I had headings with square brackets [ ] as answered in my previous question. I have changed these two things (put a line break after starting the box, and use { } for headings) to solve the problem. – Qasim Chaudhari Aug 28 '15 at 7:14