Having a ``++switch++`` and its cases wholly encompassed by a control structure such as a ``++try++``, ``++@try++``, ``++catch++``, ``++@catch++``, or a loop is perfectly acceptable. (``++try++`` and ``++catch++`` are used hereafter to refer to both variants.) It is also acceptable to have a ``++goto++`` and its target label wholly encompassed in a control structure.
What is not acceptable is using a ``++goto++`` or ``++case++`` to suddenly jump into the body of a ``++try++``, ``++catch++``, Objective-C ``++@finally++``, or loop structure. Tangling labels or ``++switch++`` blocks with other control structures results in code that is difficult, if not impossible to understand. More importantly, when it compiles (some of these constructs won't compile under ISO-conformant compilers), it can lead to unexpected results. Therefore this usage should be strictly avoided.
This {cpp} code sample, which is also applicable to Objective-C if ``++try++`` and ``++catch++`` are converted to ``++@try++`` and ``++@catch++``, demonstrates jumping into a ``++switch++`` and into a ``++try++`` and ``++catch++`` :
