A step-by-step guide for beginners to set up a mobile application development environment on Mac, Windows, and Linux.

Setting up a development environment is the first, and often the most important, step for you to learn mobile development. However, as a beginner to mobile application development, you may have many questions regarding development environment setup: What programming language should I use, Java, Objective C or Swift? What computer should I use, a Mac Book, a Windows machine, or a Linux box? What Integrated Development Environment (IDE) should I use, Eclipse, Xcode, or Android Studio? Should I start programming for iPhone, Android phone, or Windows Phone?