Changes

iPhone apps are developed using the iOS SDK in conjunction with Apple’s Xcode 4 development environment. The iOS SDK contains the development frameworks that were outlined in [[iPhone iOS 5 Architecture and SDK Frameworks]]. Xcode 4 is an integrated development environment (IDE) within which you will code, compile, test and debug your iOS iPhone applications. The Xcode 4 environment also includes a feature called Interface Builder which enables you to graphically design the user interface of your application using the components provided by the UIKit framework.