I’ve searched the web and i found interesting that the most of the people who learn a new programming language choose to build a temperature converter in their first apps created. Maybe we can call it the second Hello World
I think it is because a temperature converter uses some key features: data input, data processing and data output. Different temperatures scales make it easy to get used with selectors and buttons, and also with math.
Here is a list with temperature converter app withing different applications: