Learning iOS Development: A Hands-on Guide to the Fundamentals of iOS Programming

Classes and Objects

Objects are the heart of object-oriented programming. You define objects by building classes, which act as object creation templates. In Objective-C, a class definition specifies how to build new objects that belong to the class. To create a car object, for example, you define the Car class and then use that class to create new objects on demand. As in C, implementing a class in Objective-C is done in two places: a header file and implementation file. The header file specifies how the outside world can interact with the class: the instance variables and their types, and the methods with their arguments and any return types. It is like a contract promising how instances of your class will interface with other objects. The implementation ...