Why does SoloLearn (or any other coding app in mobile phones or tablets) takes the input *before* showing the output?

Question

Lets say I write a code which asks the user to "enter a number". When the user runs the code, it asks the user for an input. But the user doesn't know what the code is actually asking them because they haven't seen the output so how will they give the input?

Answer 1

The app doesn't actually install a compiler or interpreter for every single language it offers, instead it asks for input, and then sends the input together with the code to some servers, where the code is then evaluated. When the program is finished executing, the output is sent back to your phone, where it is finally displayed to the "console".