Question

I’m new with objective c for the iphone.

I’m writing a custom class, then, should I write my own +alloc, +init methods?
I believe that: the +alloc will just call [thing alloc]; and the +init will perform something like: [thing setValue:X];

is there a “default” +alloc and +init methods?
if yes, what should I wait for the default +alloc and +init?, let’s say i have a NSMutableDictionary*
i.e.

@interface class1 : NSObject {

    NSString *test; 
    NSMutableDictionary *map;
}

thanks

Answer 1

You generally don’t need to write your own +alloc method.

For your example, you might have an -init that looks like:

- (id)init {
    self = [super init];
    if (self) {
        map = [[NSMutableDictionary dictionary] retain];
    }
    return self;
}

Note that you first call the superclass -init, and check that it worked, before initializing your own variables.