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    <p>You actually <em>can</em> declare variables within a switch if you do it according to the syntax of the language. You're getting an error because "<code>case 0:</code>" is a label, and in C it's illegal to have a <strong>declaration</strong> as the first statement after a label — note that the compiler expects an <strong>expression</strong>, such as a method call, normal assignment, etc. (Bizarre though it may be, that's the rule.)</p> <p>When you put the NSLog() first, you avoided this limitation. You can enclose the contents of a case in { } braces to introduce a scoping block, or you can move the variable declaration outside the switch. Which you choose is a matter of personal preference. Just be aware that a variable declared in { } braces is only valid within that scope, so any other code that uses it must also appear within those braces.</p> <hr> <p><strong>Edit:</strong></p> <p>By the way, this quirk isn't as uncommon as you might think. In C and Java, it's also illegal to use a local variable declaration as the lone statement (meaning "not surrounded by braces) in a <strong>for</strong>, <strong>while</strong>, or <strong>do</strong> loop, or even in <strong>if</strong> and <strong>else</strong> clauses. (In fact, this is covered in puzzler #55 of <a href="http://www.javapuzzlers.com/" rel="noreferrer">"Java Puzzlers"</a>, which I highly recommend.) I think we generally don't write such errors to begin with because it makes little sense to declare a variable as the only statement in such contexts. With <strong>switch</strong> / <strong>case</strong> constructs, though, some people omit the braces since the <strong>break</strong> statement is the critical statement for control flow.</p> <p>To see the compiler throw fits, copy this horrific, pointless snippet into your (Objective-)C code:</p> <pre><code>if (1) int i; else int i; for (int answer = 1; answer &lt;= 42; answer ++) int i; while (1) int i; do int i; while (1); </code></pre> <p>Yet another reason to always use { } braces to delimit the body of such constructs. :-)</p>
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    1. COwow, thats weird... but thanks!
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    2. COGenerally, if the variable is used only within the single case, then enclosing the case section in { } will be better form (it avoids it being accidently reused later). If the variable is used againlater, then it really makes more sense to declare it before the start of the switch statement, since its very obtuse otherwise.
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    3. COI totally agree, using a nested scope with braces does make the intent crystal clear and can prevent incidental bugs. Thanks for clarifying!
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