Data Structure 5

a. Consider a doubly linked list with its node structure defined as follows: typedef struct node *node_pointer; typedef struct node (node_pointer llink; int id; node_pointer rlink;) The procedure below insert(node_pointer ptr, node_pointer newnode) inserts newnode to the left of the node ptr. There are 4 statements a, b, c and d in the procedure. It is possible to arrange the statements in a different order and the resulting code would still work properly. Identify one possible sequence of the statements which can cause a problem to the procedure. Explain clearly why it would not work. void insert (node_pointer ptr, node_pointer newnode) f // to insert newnode to the left of any node ptr in a doubly linked list newnode->rlink ptri II statement a //statement b //statement c /Istatement d ptrllink-rlink-ptr ptr1 link = newnode