Here's a snippet from the terminal after fixing the forward(); and adding some serial.print to give me an indication of what it's doing:
front 0
front 0
front 0
front 0
front 0
front 0
front 0
front 11
left ping 7
right ping 6
turning left
front 9
left ping 0
right ping 0
turning left
front 0
front 0
front 0