is an Objective-C convenience that automates the creation of getters and setters for your class. In Chapter 5, you defined a Shape class and manually defined the getters and setters. Here is the Shape class definition without using properties:
A property provides a simple way to implement an object’s getter and setter methods. @property is used to define a property, and @synthesize is then used to generate the getter and setter for the property.
You can automate the creation of the getter and setter methods ...