First, are you meaning to call a sub routine? $r=c($w/24); If you are, you need to post it. When I change that line to $r=($w/24); I get the same answer as java.

As for prototyping in another language, I tend to avoid it. Each language will have some features/bugs that don't exist in the language you are prototyping in, which can either cause problems in the conversion, or not let you make use of the features of that language.