Could I use Java or c#? [was: Re: re-writing college books]

[sasa at pheniscidae.tvnetwork.hu (SZALAY Attila)]

Hi All!

I read this thread and I little be afraid. I'm just ahead of a complete
rewriting of my program. The previous code was written in pure C (with
an OOP looks-like somewhere).

This program should run on Linux, freebsd and windows platform. This
program is a GUI, so it has a graphical interface too but do a lot of
computing and xml handling.

I know C the most, so C++ is the least step I have to do. But I'm
uncertain now that this is enough. When I have looked around for OO
alternatives the C# was dropped, because I couldn't find a
cross-platform graphical tools and Java was dropped because it's speed
and the possibilities of debugging problems.

Is there any other alternatives or I left something or the C++ is the
only alternative for me?