How to add notifications to icon in iOS application

Question

I see that some applications in iPhone show a red circle with the number of notifications from the application, how is that done?

Answer 1

[[UIApplication sharedApplication] setApplicationIconBadgeNumber:99]

Zero value hides the badge.

Answer 2

It is called a Badge, and it is used for icons, tabbaritems mostly.

You can set it up like

UITabBarItem *featured = [[UITabBarItem alloc] initWithTabBarSystemItem:UITabBarSystemItemFeatured tag:0]; 
featured.badgeValue = @"1";