Grep

Hello there. My first post.

I have just completed semester one at university. The final assignment was to attempt to write in plain ANSI C our own GREP programmes. We didn't actually have to produce a working version, which is lucky since I couldn't; we just had to work on it and show that we were having a bash at it. So, that assignment and semester one are over, but I still wish to create this programme. After that, I would like to write several other tools just for learning how to do it. So, does anyone have any hints, any method for using wildcards in strings, et cetera?

Thanks.