To answer your question, prototype and test the algorithm in as many languages as you are willing to debug. Personally, I'd prototype in whatever language I was going to implement in. While good algorithms are language agnostic, debugging is not. If you use a good algorithm, it will look mostly the same regardless of whether you write the code in C, Perl or Java - but there will be differences in implementation (like casting in a strongly typed language).

In your snippet, perl does exactly what I would expect - the algorithm is fine. It's the java implementation that fails.

Take a look at the following snippet, and see if it produces the results you expect with different values of w.

public class HelloWorld {
  public static void main(String[] args) {
    int w=Integer.parseInt(args[0]);
        
    System.out.println("No cast: " + Math.ceil (w / 24));
    System.out.println("Divide, then cast: " + Math.ceil ((double) (w 
+/ 24)));
    System.out.println("Cast, then divide: " + Math.ceil ((double) w /
+ 24));
  }
}
[download]

Maybe this thread should be posted at http://javajunkies.org ;-)