The Arduino IDE supports multiple files by adding more tabs. If you use INO files you’re only adding one at a time, but if you use C/C++ header and source files it’s two at time.

WifiDuino has been designed to offer users an open-source Arduino-compatible, wifi-enabled board. Enabling makers and developers to use Arduino IDE (Integrated Development Environment) interface ...

Arduino simplifies things by only using just one coding language. Here's what you need to get started with developing software for the tiny device.