Why is a cast needed here?

ios, objective-c

Solution

It's not necessary. The cast is simply for clarity, as the property is already defined as a `NSDate`, here:

@property (nonatomic, strong) NSDate *date;

The only situation where a cast would be necessary in that form would either be in non-arc when dealing with core foundation, like this:

CFDateRef asCFDate;
NSDate *asNSDate = (NSDate *) asCFDate;

However, in ARC, you would use a `__bridge` cast instead.

Problem

I've been working through Apple's "Your Second IOS App" tutorial" and I've noticed that every time I use an `NSDateFormatter` for producing a date string I am expected to cast the input date object. e.g. (Page - under "To implement the configureView method") ``` BirdSighting *theSighting = self.sighting; if (theSighting) { self.birdNameLabel.text = [theSighting name]; self.locationLabel.text = [theSighting location]; self.dateLabel.text = [formatter stringFromDate:(NSDate *)theSighting.date]; // Here } ``` However I know that in the `BirdSighting` class that the `date` property is always an `NSDate` object. So I was wondering why the tutorial always casts the input, is there some sort of objective-c convention or framework convetion that recommends that you do this? and if so why?

Original source