Video Tutorial: Objective-C Memory Management (Manual)

Challenge

Your challenge is to add a new “Closet” class to the demo project, using manual memory management, so that this code works:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    Person *ray = [[Person alloc] initWithName:@"Ray"];
    Person *vicki = [[Person alloc] initWithName:@"Vicki"];
    
    Closet *closet = [[Closet alloc] init];
    
    ray.sweater = closet.graySweaterSlot;
    closet.graySweaterSlot = nil;
    
    vicki.sweater = closet.blueSweaterSlot;
    closet.blueSweaterSlot = nil;

    closet.blueSweaterSlot = vicki.sweater;
    vicki.sweater = ray.sweater;
    ray.sweater = nil;

    [ray release];
    [vicki release];
    [closet release];
    return YES;
}

Download demo code

Download solution

Helpful links

• Memory Management Tutorial for iOS
• Instruments Tutorial for iOS: How to Debug Memory Leaks
• Properties Tutorial for iOS

Errata

• Around 8:28, I said “you always have to call super dealloc first”. This is a bit confusing, because actually it’s best practice to put the call to [super dealloc] at the end of the method, as shown in the video. It would have been more clear if I had said “you always have to call super dealloc at the end of dealloc if you are not using ARC”.
• Audio was cut off around the 15:00 mark – it should have said “when you call init, by convention, it returns an object with retain count of 1”.