21. Writing iOS Applications

In this chapter, you’ll develop two simple iPhone applications. The first illustrates some fundamental concepts to familiarize you with using Interface Builder, making connections, and understanding delegates, outlets, and actions. For the second iPhone application, you’ll build a fraction calculator. It combines what you learned while developing the first application with what you learned throughout the rest of the book. The same principles you learn here can be used to develop applications for other iOS devices as well.

The iOS SDK

To write an iPhone application, you have to install Xcode and the iOS SDK. This SDK is available free of charge from Apple’s Web site. To download the SDK, you’ll need to first register ...

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