Unclear wording on ex13.

ex13.tex

@@ -89,7 +89,7 @@ \section{How To Break It}
 \item Accidentally put in variable into the \ident{switch} that
     evaluates to something unexpected, like an \ident{int}
     that becomes weird values.
-\item Use initialized values in the test.
+\item Use uninitialized values in the \ident{switch}.
 \end{enumerate}
 
 You can also break this program in a few other ways.  See if you