Assiging base class pointer to derived class in objective c

Question

I have a base class called ModelBase and I have a derived class called "Person". Now in the init method of person, I have something like

-(Person*) init {
     if(self = [super init])
         return self;

     return nil; 
}

However, Objective C complains that Incompatible Objective-C types initializing 'struct ModelBase *', expected 'struct Person *'. I'm only initializing self with [super init] which is initializing a base class pointer to a derived class.

What am I missing?

Answer 1

Did you declare your ModelBase init method to return (ModelBase*) ? If so, change it to return (id) instead. You'll notice that most initializers in Cocoa return (id) for this very reason.

Instead of

- (ModelBase*)init;

you want

- (id)init;