Switch case is always defaulting in TinkerCAD circuit editor

Community General Discussion
2

Try including a reference.

Although "C" works in the Arduino IDE, much of clang is built-in to the Arduino IDE.

Your sketch is printing "Problem" because it is falling-through the Serial input.

Here is Arduino's "Serial" page: https://docs.arduino.cc/language-reference/en/functions/communication/serial/

Here is @Robin2 's highly-recommended, well-documented "Serial Input Basics": Serial Input Basics - updated