File supplied.o contains code that can build, display, and destroy a doubly linked list.

For this lab, you will need to write the following two functions in dlist.cpp, and add function prototypes for them to dlist.h.

void duplicate(node * head, node *& newHead)

recursively create a copy of the source list with head where newhead is the head of the destination list.

int removeTwo(node *& head)

recursively remove all the 2s from the list