Question

I have a “Note” class, and I have a Tuner Class. My Tuner class is initializing an NSArray* in it’s init function.

I want to initialize this array to hold 88 notes, and right now I am creating things like Note* key1; etc etc.

I am just making sure that I need to alloc things for these notes so that they do not go out of scope once init finishes, and my NSArray stays in tact with its entries, or am I able to just declare Note key1 and insert into the array and it is taken care of for me.
An example piece of code creating an NSArray containing a few objects such that the array will stay around even after the function exits would be very helpful. Thank you!

Answer 1

NSArray and NSMutableArray send -retain to objects when they are added, so the appropriate thing to do is to -release the objects you add explicitly or use autoreleased objects.

Here’s a quick example for the Tuner class’s -init method:

- ( id )init
{
    NSInteger    i;
    Note         *note;

    self = [ super init ];
    if ( self ) {
        notes = [[ NSMutableArray alloc ] initWithCapacity: 88 ];
        for ( i = 0; i < 88; i++ ) {
            note = [[ Note alloc ] initWithKey: i ];
            [ notes addObject: note ];
            [ note release ];
        }
    }

    return( self );
}

You will need to +alloc every Note object and -release it, since adding it to the array retains it. To destroy all the note objects when you’re done, make sure your Tuner class releases the array in its -dealloc method:

- ( void )dealloc
{
    [ notes release ]; // this sends release to all objects in the array, too

    [ super dealloc ];
}