I want to study coding theory, but I don't know any text book about. Can anyone indicate to me some book? I'm in the last year of undergraduate mathematics course, so I would of a basic book, but that provides to me an experience in this field.
Peruse them online and see if they agree with you, they are not in any particular order and I may have missed a couple.
Note: there are also graduate level books in this area.
Other Potential Sources
Another nice resource which IIRC has a decent amount of coding theory is the excellent Information Theory, Inference, and Learning Algorithms by David MacKay. It's a published book but it is also available online at http://www.inference.phy.cam.ac.uk/itila/book.html