Learning Objective-C 2.0: A Hands-On Guide to Objective-C for Mac and iOS Developers

12. Properties

One of the most common programming tasks is to set or retrieve a value held in one of an object’s instance variables. Although it is possible in some cases to access the instance variable directly, doing so is a bad practice. The correct way to access an instance variable is to write accessor methods. An accessor method that sets an instance variable’s value is called a setter and one that returns an instance variable’s value is called a getter.

For example, if your object has integer instance variable numberOfDogs, you should declare and implement the following two methods:

-(int) numberOfDogs; // returns the current value

-(void) setNumberOfDogs:(int) newNumberOfDogs; // sets a new value

Note

Naming the getter instanceVariableName ...