Using a Switch Statement in Obj-C

Question

Below is a Switch / Case statement that displays an error message when an email cannot be sent. For the most part, everything seems right, but when I place a UIAlertView into the Switch Statement I get an error in Xcode:

Xcode error

switch (result) {
    case MFMailComposeResultCancelled:
        NSLog(@"Result: Mail sending canceled");
        break;
    case MFMailComposeResultFailed:
        NSLog(@"Result: Mail sending failed");
        UIAlertView *message = [[UIAlertView alloc] initWithTitle:@"Sending Failed"
                                                          message:@"The email could not be sent."
                                                         delegate:nil
                                                cancelButtonTitle:@"OK"
                                                otherButtonTitles:nil];

        [message show];
        break;
    default:
        NSLog(@"Result: Mail not sent");
        break;
}

Why does it generate an error when I place code inside the case?

look at[enter link description here][1] [1]: http://stackoverflow.com/questions/366073/instantiating-new-object-within-switch-block-why-does-it-fail — TompaLompa, Mar 30 '12 at 15:00
possible duplicate of [When converting a project to use ARC what does "switch case is in protected scope" mean?](http://stackoverflow.com/questions/7562199/when-converting-a-project-to-use-arc-what-does-switch-case-is-in-protected-scop) — ughoavgfhw, Mar 30 '12 at 15:04

score 14 · Accepted Answer · answered Mar 30 '12 at 15:00

Put it in brackets:

case MFMailComposeResultFailed: {
    NSLog(@"Result: Mail sending failed");
    UIAlertView *message = [[UIAlertView alloc] initWithTitle:@"Sending Failed"
                                                      message:@"The email could not be sent."
                                                     delegate:nil
                                            cancelButtonTitle:@"OK"
                                            otherButtonTitles:nil];

    [message show];
    break;
  }

See @Phillip Mills answer or do a search, and you will find lots of explanations. — bandejapaisa, Apr 02 '13 at 13:50

score 12 · Answer 2 · answered Mar 30 '12 at 15:01

The problem is declaring variables inside cases of a switch. The compiler is upset about trying to figure out scope when only some of the code is executed. If you put brackets around the contents of the 'fail' case, it should be OK since that restricts the scope.

Using a Switch Statement in Obj-C

2 Answers2