An usefull app for emergency cases, especially when you are new to the city and don't know the locations, is the gouvernment issued "Apel 112" phone app. It will automatically send your location when you call through the app so emergency responders can get to you as fast as possible.
This application is verry useful for using the public transportation in Cluj Napoca. Google Maps works verry well for walking on foot, and it can also be used to see bus information in a pinch, but "Moovit" will have more accurate and up-to-date timetables and information about which bus to take.
If you are an expert in using transportation apps, and have gotten a little familiar with the Cluj Napoca public transportation system, you can also use app "Tranzy". This will show you the location of your bus in real time and can be verry usefull if you know how to use it.