What would happen If I rebooted my IPhone 4S?

I want to know what would happen If I rebooted my IPhone 4S… One of my apps keeps crashing and some people are telling me to Reboot my phone… I'm Not resetting it, because I know it would delete everything. I just want to know if it would delete all my phone data (Music, Apps, Games, etc.) I know how to reboot it (Hold the HOME and SLEEP for 15 seconds) I just really want to know if it will delete anything.

Nothing is deleted.

It just forces every application to fully quit running and then totally powers down the phone until you restart it. Any misbehaving apps then have to reload themselves when you open them and that will hopefully get them to run correctly again.