Date compare Best Practices

Hi,
I am looking to take two dates entered and passed to a work file build program. 
They are passed as MMDDYYYY from and to dates. They will be compared with from 
and to dates in a master file and then records are selected that pass. Since I 
have already written the first program that accepts the entry from the user I 
can perhaps change my order in the program there. THe presentation to the user 
must be in the order described. So far I can only recall that I would take each 
date and rearrange it with a series of MOVES into a Data Structure. I am 
interested if there are better ways again unfortunately in the older versions 
of RPG.
Thanks,
Rob