After seeing how classes and objects work in Objective-C, this part will be completely dedicated to types in Objective-C. This feature comes straight from C, but it’s still extensively used in Objective-C programming, including Apple libraries. Since you will encounter this quite often, it’s worth to spend some time having a look at this feature.

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Defining custom types
Constants and enumerations
Bitwise operators and bitmasks
Structures

Now that we know how to create our own classes, we will go over some useful features of the languages to deal with the organization of class interfaces and memory management.

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Categories
Protocols
ARC and memory management

After seeing in the second part of this guide how to create and use objects, now we will see how we can create our own classes.

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Classes
Headers, importing and forward declarations
Properties and instance variables
Initialization

After having seen in the first part of this guide the basic control structures that Objective-C inherits from C, in this second part we will have a look at how we use objects and collections in Objective-C.

Table of contents

Method calling
A note about messaging
Class methods and object creation
Working with nil
Values and literals
Collections

When, as a developer, you come from another language to Objective-C, you usually want to map the general concepts about programming you already know to this new language that at first might seems obscure. I remember myself being confused by the Objective-C syntax when I started learning it. What at first look might not make sense actually does a lot when you get a grasp of it and in my opinion (and the opinion of many other developers) makes the code much more readable. What at first sight might seem complicated is just something a bit different from what you are used to, thus feeling unfamiliar.