21. Writing iOS Applications

In this chapter, you develop two simple iPhone applications. The first illustrates some fundamental concepts related to using the interface design tool built in to Xcode, making connections, and understanding delegates, outlets, and actions. For the second iPhone application, you 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.


To write an iPhone application, you have to install Xcode and the iOS software development kit (SDK). This SDK is available free of charge from Apple’s Web site. To download the ...

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