iOS is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that presently powers many of the company's mobile devices, including the iPhone, iPad, iPod touch. To develop applications you should have Xcode IDE, which supports both Objective-C and Swift languages. Xcode IDE can be installed only in MacOS i You can write code in both Objective-C and Swift Languages. Swift is an alternative to the Objective-C language that employs modern programming-language theory concepts and strives to present a simpler syntax.