stuck on "while" statement

The syntax of your switch statement is wrong. It may compile, but it's not semantically correct.

see: http://arduino.cc/en/Reference/SwitchCase

You have to use the literal word "case" for each value of the statement. Do not put statements before the first case, that's undefined behavior.

See the code section of this playground entry for an example:
http://arduino.cc/playground/Main/ShowInfo