HTML isn't really a programming language.
Should that be windows.h?
I would suggest running the study for more than just a few days . . . I mean, it ends tomorrow! I'd give it a week at least. Some internet users have a weekly cycle. (Like me.) If you do the survery for a week, you'll catch the people who only go online on Tuesdays etc.
Some of the questions are negative -- "Code is not understandable at all" -- and some are positive -- "There are unneeded intermediate steps". If I didn't understand the code at all, I'd have to click yes for some questions and no for others. I'd change that if possible.
The code is not of the best standard in many ways, and most of it wouldn't even compile. Count the quotes here.
 Just realized that the quotes were intentional. It didn't look it in the original font. Perhaps a monospace font would be a good idea. [/edit]
Why is there a semicolon after the closing brace in main() for question 5? Indentation is inconsistent (watch out for Elysia!) -- some lines have several statements. etc, etc.