There is not much that I can comment about this app, Its one of the best out there which TEACHES YOU CODING FOR FREE man what else do you need. Maybe it dosnt teaches you at an expert level but yeah for beginners coding was never that easy with your mobile actually being your code testing arena, therefore for me its a must and also for everyone else who is new and is trying to learn coding.
It also has a stage wise assortment of different concepts while a complete library of searchable sub concepts. please try it, I personally request you.
ITS THE PLACE YOU CAN TURN FROM A ZERO TO A SKILLED HERO CODER< SO DONT FORGET TO TRY IT OUT.