linked list implementing the position adt this class is similar to class dnode shown in code fragment except that now our nodes store generic element instead of character string note that the prev and next instance variables in the dnode class below are private references to other dnode objects code fragment class dnode realizing node of doubly linked list and implementing the position interface (adtgiven position in swe can "unwrapp to reveal the underlying node this is accomplished by casting the position to node once we have node vwe canfor exampleimplement method prev(pwith getprev (unless the node returned by getprev is the headerin which case we signal an errorthereforepositions in doubly linked list implementation can be supported in an object-oriented way without any additional time or space overhead consider how we might implement the addafter(pemethodfor inserting an element after position similar to the discussion in section we create