Getting access denied error while updating list items

I was getting access denied error while updating list items, I already tried to put my code into SPSecurity.RunWithElevatedPrivileges delegate, still I was getting error. Below was my actual code.

CODE:

//code line for updating list columns

Listitem.update()

List.Update()

After doing debugging and removing line by line from actual code I have figured out actual problem – the user who has contributor rights(normal user) was getting access denied error, admin users can able to update list without any problem, it’s because of LIST.UPDATE() statement, because contributor rights users don’t have permission to change anything into List settings, they can add/delete list items but they can’t able to change anything into list, after removing LIST.UPDATE() statement from my actual code, all users were able to successfully update the list items.