Expected Expression before ... In Switch Statement

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Why can't variables be declared in a switch statement? 23 answers

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Switch statements don't introduce new scopes. What's more, according to the C language spec, a regular statement must follow a case statement - a variable declaration is not allowed. You could put a ; before your variable declaration and the compiler would accept it, but the variable that you defined would be in the scope of the switch's parent, which means you cannot re-declare the variable inside another case statement.

Typically when one defines variables inside of case statements, one introduces a new scope for the case statement, as in

switch(event) {
    case kCFStreamEventHasBytesAvailable: {
        // do stuff here
        break;
    }
    case ...
}

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