A Class can simply be defined as a representation of a type of object; think of it as a blueprint that describes the object. Just as a single blueprint can be used to build multiple versions of a car engine, a class can be used to create multiple copies of an object. In Objective-C, you will spend most of your time dealing with classes and class objects. An example of a class object is the
NSObject is the root class of most of the Objective-C classes. It defines the basic interface of a class and contains methods that are common to all classes that inherit from it.
To declare a class, you use the @interface compiler directive that is declared within
MyClass.h, as follows:
@interface MyClass ...