OS is the intuitive, advanced, intelligent and secure mobile operating system. It’s the foundation of iPhone, iPad and iPod touch. It comes with a collection of apps and features that let you do the everyday things, and the not-so-everyday things, in ways that are intuitive, simple and fun. iOS development targets the Apple's iPhones and iPads. The users of Apple devices expect very responsive applications with polished and intuitive user interface. The hardware in iPhones and iPads is very powerful: applications that take advantage of the CPU, GPU and DSP can deliver truly amazing features with low power requirements. iOS is a good choice if you want to avoid having to test your application on a large number of devices and OS versions—as is the case with Android. Nevertheless, if you are targeting general public, you must embrace iOS as well as Android—and, depending on your expected user base—Windows Phone platforms.
Swift is a powerful and intuitive programming language for iOS, OS X, tvOS, and watchOS. Writing Swift code is interactive and fun, the syntax is concise yet expressive, and apps run lightning-fast. Swift is ready for your next project — or addition into your current app — because Swift code works side-by-side with Objective-C.