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Introduction

Contents:

Who Should Read This Document
Organization of This Document
See Also

An object-oriented approach to application development makes programs more intuitive to design, faster to develop, more amenable to modification, and easier to understand. Most object-oriented development environments consist of at least three parts:

• A library of objects

• A set of development tools

• An object-oriented programming language and support library

The Objective-C language is a simple computer language designed to enable sophisticated object-oriented programming. Objective-C is defined as a small but powerful set of extensions to the standard ANSI C language. Its additions to C are mostly based on Smalltalk, one of the first object-oriented programming languages. Objective-C is designed to give C full object-oriented programming capabilities, and to do so in a simple and straightforward way.

For those who have never used object-oriented programming to create applications before, this document is designed to help you become familiar with object-oriented development. It spells out some of the implications of object-oriented design and gives you a flavor of what writing an object-oriented program is really like.

Who Should Read This Document

The document is intended for readers who might be interested in:

• Learning about object-oriented programming

• Finding out about the basis for the Cocoa application framework

• Programming in Objective-C

This document introduces the object-oriented model that Objective-C is based upon.

Because this isn’t a document about C, it assumes some prior acquaintance with that language. However, it doesn’t have to be an extensive acquaintance. Object-oriented programming in Objective-C is sufficiently different from procedural programming in ANSI C that you won’t be hampered if you’re not an experienced C programmer.

Organization of This Document

This document is divided into several chapters:

• “Why Objective-C?” explains why Objective-C was chosen as the development language for the Cocoa frameworks.

• “Object-Oriented Programming” discusses the rationale for object-oriented programming languages and introduces much of the terminology. It develops the ideas behind object-oriented programming techniques. Even if you’re already familiar with object-oriented programming, you are encouraged to read this chapter to gain a sense of the Objective-C perspective on object-orientation and its use of terminology.

• “The Object Model”

• “Structuring Programs”

• “Structuring the Programming Task”

See Also

The Objective-C 2.0 Programming Language describes the Objective-C programming language.

Objective-C 2.0 Runtime Programming Guide describes how you can interact with the Objective-C runtime.

Objective-C 2.0 Runtime Reference describes the data structures and functions of the Objective-C runtime support library. Your programs can use these interfaces to interact with the Objective-C runtime system. For example, you can add classes or methods, or obtain a list of all class definitions for loaded classes.

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