what's meant by "Unicode characters"?

Please try and give better titles for quicker response. Also that helps in more people actually reading your threads. I have edited the title for you as of now.

Now about your query.

Unicode characters mean A 16-bit character encoding scheme allowing characters from lots of other languages like Arabic, Hebrew, Chinese, Japanese, to be encoded in a single character set.

Let us know what compiler you are using to compile your code as well. In VS you may be using the char data type as something like _TCHAR or _WCHAR and that means it could be a Unicode compatible code and then you need to see the project setting to see if it is using the Unicode compilation command line.

Also your main will be a bit different but I don't remember what it is right now

 

So now I think you should be able to tell if its Unicode or not from the above post