C ebooks

http://www.le.ac.uk/cc/tutorials/c/

why use C , contrl loops , variable declaration ,.... for beginners

http://www.physics.drexel.edu/courses/CompPhys/General/C_basics/c_tutorial.html

Pointers , arrays,...

http://www.howstuffworks.com/c.htm

C tutorial by questions... not for beginners

http://www.iu.hio.no/~mark/CTutorial/CTutorial.html

introduction , libraries , comments, parameters... good