iOS is a mobile operating system developed and distributed by Apple Inc. It was originally released in 2007 for the iPhone, iPod Touch, and Apple TV. iOS is derived from OS X, with which it shares the Darwin foundation. iOS is Apple's mobile version of the OS X operating system used in Apple computers.
Before proceeding with this tutorial, you should have a basic understanding of Computer Programming terminologies. A basic understanding of any of the programming languages, especially Objective C programming language, will help you learn the concepts of iOS programming faster.