please help me to design an editor which helps c programming..

Exactly what is your contribution to this effort so far?
http://www.daniweb.com/forums/announcement118-2.html

I may help if i knew how far you actually are. It is not very difficult to write a simple text editor from scratch, first you likely have to implement a doubly linked list of pointers to lines, at least this is how it is implemented in many text editors. I have not so much experience with text editors, but i once ported to windows an old editor stevie, and replaced its regular expressions with public domain regular expressions, so that it's completely public domain... You should at least implement regular expression and command filtering, this is kind of minimal for a programmers editor... You can even take code from editors like stevie, as this is public domain, to be honest, i know no other public domain text editors, there can be a few, but there are not many such.

Attached is the source code of the editor stevie which also works in windows.