int tag = FindValidTag(code);
This is the call to the function that compares the RFID tag read in to the known values. That function returns 0 if the tag is unknown, or 1 through 5 for each of the known tags.
The return code is stored in tag.
if(tag > 0 && tag <= ledCnt) digitalWrite(LED[tag-1], HIGH);
This code lights up an LED, based on which tag is read. There are 5 LEDs. There is a red one, a blue one, a yellow one, and 2 white ones. I light up an LED that is the same color as the scanned fob or card, since I had LEDs the same color.
This code was just to verify that the RFID was working. The real application for the RFID reader will do more than light LEDs.