What kind of parameters can be used in c#

http://www.dotnetperls.com/parameter

http://www.c-sharpcorner.com/UploadFile/mahakgupta/working-with-ref-and-out-parameter-in-C-Sharp/

http://www.codeproject.com/Questions/117093/What-is-the-difference-between-the-ref-and-out-key