Some help with loops

I have the following code which loads a NetCDF file, flips it around a few times then saves it as a ASCII file

ncload('20030101_Sg.nc')
twodim=squeeze(Sg)
a=rot90(twodim)
b=rot90(a)
final=fliplr(b)
dlmwrite('20030101_Sg.txt',final)

There are 365 of these NetCDF files in the folder and I want to loop this code to get ASCII outputs of all of them. As above I need the ASCII file name to be the same as the NetCDF file name.

Any help would be appreciated, I'm quite new to Matlab.