The iOS app may be developed on computers runing macOS 10.12 and above using Xcode (available on App Store). It should be target at iOS 11.0 and above, and can be built with Swift and Objective-C.
Swift is preferred as it is faster, safer, and more interactive. It removes pointers and other unsafe access in Objective-C, and switches from the smalltalk-style syntax used by Objective-C to dot notation. All the sample code in this chapter is written in Swift.