Originally Posted by DaWei
I told you in the above response what you should provide if you want more help. Rather than do that, you have just replicated your insufficient post. I assure you that I can build a working doubly-linked list. I can also assure you that I'm not going to write your code for you, or guess at what unseen things you are doing.
In fact if used the search feature he may had the solution as well because its already here.