Working out which way to rotate?

Hello! Im trying to work out how to calculate which way to rotate an active towards a new angle, based on which way would be quickest. If I say like

If active angle < new angle
angle ++

If active angle > new angle
angle --

then I get problems if say the new angle is 340 and current angle is 20 because the active rotates the full 320 degrees round instead of 40 the other way because it is indeed less then 340. Hope that makes sense, I basically cant get my head around calculating the difference between 2 angles. Any help appreciates, cheers!

*Edit* Just seen Direction Calculator works for this, but for 32 directions.

*Edit 2* http://www.clickteam.com/epicenter/ubbthreads.php?ubb=showflat&Number=14722&page=0&fp art=1
Now my objects turn the right way :)

gotta figure out the difference between the two angles now, shouldnt be too hard. Sorry for the rather pointless post :blush: