how does the reaping system work?

The reaping system is a sort of lottery which takes one boy and one girl from districts 1 through 12 every year. THe kids are 12 through 18 years old. These people fight it out in an arena largely for the elite's enjoyment who live in the capitol. The names are supposedly picked out randomly. Kids can volunteer themselves, like Katniss did, in place of a person picked.

That's scary...

Is there lots of death? And violence in the movie?