i made a calculator 

Update 2013, This was in late 2008, I am working on a web version of this which can actually display graphs, but I do not currently have a server to display it to the public.

I made this calculator out of a parser gotten from a the book: The Art Of Java.

Version 2 is out, I modified the books parser to allow functions and constants.  It now has two constants and a variety of functions, including sine, cosine, and tangent, as well as their inverses. it also includes one variable for the previous answer.  as well as maintaining 26 (letters) variables.

to download click here 

                                           (actual size, resizable)