Can anyone explain this Java logic (Security problem*) ?

Question

I used to solve this security problem in another method but im not able get the logic of the below code, so can anyone explain this below logic ?

The code is :

https://code.sololearn.com/cdcK17w6jaLC/?ref=app

Answer 1

There will be setted an indicator = 1 when will come $ or T.

Then when after that the indicator equals to 1 will come $ or T the output will be ALARM.

But when after that will come G that means G is between of $ and T and the output equals to quiet.

Answer 2

Thank you bro