Line-following robot query

Hello,
If I have a code for a line following robot, and i would like to write a library, i have made different .h and .cpp files for my 4 motors and my 2 sensors. The question i have is what do you put under the void part in the .h file under the public section for lets say the sensorleft.
Thanks

i have made different .h and .cpp files for my 4 motors and my 2 sensors.

Where are they?

The question i have is what do you put under the void part in the .h file

The void part?

Don't double post:
http://forum.arduino.cc//index.php?topic=193757.0