What is iOS?
iOS is a mobile operating system created by Apple in 2007 for the iPhone. It was later extended to support other Apple mobile devices, such as the iPad and iPod Touch. iOS applications can be developed in Objective-C and Swift. Swift is interoperable with Objective-C, so both languages may be used in the same application. Since Objective-C is a strict superset of C, C may also be used. Objective-C++/C++ are also supported. Apple's XCode IDE is the standard for iOS development, though JetBrains does offer an alternative option called AppCode. In contrast to Google's Android, Apple maintains strict control over the distribution of iOS apps. Unless an iOS user jailbreaks their device, apps may only be installed through the App Store, where they must be reviewed by Apple before they may be released. Users with "caged" (non-jailbroken) devices may still install enterprise apps through third party sources, but unless the device is configured through Mobile Device Management, the application will not be useable until the user goes through a convoluted approval process.