iOS Development Basics Ivars (instance variables) and @property (attributes)

<span id="Label3"><p>Objective-c has brought a major improvement that Non-fragile ivar. So that I a class can arbitrarily increase the instance variable, do not have to recompile the child class. is of great significance to framework developers such as Apple.</p><p>The latest compiler supports @property to automatically synthesize instance Variables. equals the Ivar+getter+setter method.</p>