The concept of doubly linked list

Understanding the concept of doubly linked list: How to modify a doubly linked 1.creatting reverseShow function. 2.Insert a node with elem value of 100 to the front of the list. 3.Insert a node with elem value of -99 to the back of the list. 4.Remove the first node from the front. 5.Remove the first node from the back. 6.Find the third node from the back. 7.Delete the third node