Instance variable not retaining value in iOS application

Question

I have declared this ivar in my

ViewController.h

#import 

@interface FirstViewController : UIViewController 

        

Answer 1

NSArray *sortedCountries = [[countries sortedArrayUsingDescriptors:[NSArray arrayWithObject:descriptor]]retain];

to

self.sortedCountries = [countries sortedArrayUsingDescriptors:[NSArray arrayWithObject:descriptor]];