1. Last meeting..Doubly Linked List  InsertToFront  InsertToEnd  Search  DeleteNode

2. InsertToFront  next of new node points to head  prev of node pointed by head points to new node  head pointer points to new node

3. InsertToEnd  next of tail points to new node  prev of tail points to node pointed by tail  tail pointer points to new node

4. With Doubly Linked List, we can traverse the nodes from tail to head 10 1515 7 headptr tailptr null null data prevnext

5. Create Node Code typedef struct node * nodeptr; nodeptr headptr,tailptr,newnode; struct node{ char * name; char * name; int age; int age; char * address; char * address; nodeptr prev, next; nodeptr prev, next;}; node * create_node(char in_name[],int in_age,char in_address[]) { node *t = new node; node *t = new node; t->name = new char[strlen(in_name)+1]; t->name = new char[strlen(in_name)+1]; t->address = new char[strlen(in_address)+1]; t->address = new char[strlen(in_address)+1]; t->age = in_age t->age = in_age strcpy(t->name,in_name); strcpy(t->name,in_name); strcpy(t->address,in_address); strcpy(t->address,in_address); t->next=NULL; t->next=NULL; t->prev=NULL; t->prev=NULL; } return t;

6. Circular Doubly Linked List Functions  Create Node  Insert in the Beginning  Insert in the End  Search A Node  Delete A Node

7. Insert a Node in the Front void InsertFront(nodeptr newnode) { if (headptr==NULL) tailptr=headptr; tailptr=headptr; 10 1515 7 headptr data newnode newnode->next = headptr; headptr->prev=newnode; headptr=newnode;} newnode->prev = tailptr; tailptr->next = newnode; tailptr

8. Inserting in Front: Reminders  prev of head should properly point to tail  head should point to the new node

9. Insert a Node in the End void InsertTail(nodeptr newnode) { if (tailptr==NULL) headptr=tailptr; headptr=tailptr; 10 1515 7 headptr data newnode tailptr tailptr->next =newnode; newnode->prev=tailptr; tailptr=newnode;headptr->prev=tailptr}

10. Insert Node at End:Reminders  next of tail should point to head  prev of head should point to tail

11. Bonus Question:  What if you do not have a tail pointer? How should you keep track the end of the list?

12. Searching…  is basically a sequential search..  inspect each data of the node if it is the key.  is similar to SearchNode of Linked list and Doubly Linked List  BUT, be cautious of the HEAD and the TAIL…this will create trouble

13. Searching a node nodeptr SearchNodeFromTail(char *key) {bool found; nodeptr cursor=tailptr; while (cursor!=NULL && !found) { if (strcmp(cursor->name,key)==0 found=true; found=true;else cursor=cursor->prev; cursor=cursor->prev; }; return cursor; } nodeptr SearchNodeFromHeadchar *key) {bool found; nodeptr cursor=headptr; while (cursor!=NULL && !found) { if (strcmp(cursor->name,key)==0 found=true; found=true;else cursor=cursor->next; cursor=cursor->next; }; return cursor; } For a bonus mark of 1, can you tell if there’s something wrong in these 2 functions? Discuss.

14. Deleting a node 10 1515 7 cursor Modify SearchNode 1. Declare a nodeptr prev; 2. Let prev follow cursor before it goes to next prev 8 null null

15. Modify SearchNode 1. Declare a nodeptr prev; 2. Let prev follow cursor before it goes to next 3. If the key is found; let next of prev point to next of cursor and previous of the next of cursor point to the previous of the cursor 10 1515 7 cursor prev 8 null null Deleting a node

16. Deleting a Node Modify SearchNode 1. Declare a nodeptr prev; 2. Let prev follow cursor before it goes to next 3. If the key is found; let next of prev point to next of cursor 4. Delete node pointed by cursor 10 1515 cursor prev 87

17. Applications of Linked List  database records  preliminary for advanced data structures such as binary trees, heaps,etc  computing power is based on linked list

18. Bonus Questions:  What type of linked list will you use for the BUSIT bus routes (From Transport Center to Sub-urbs)  How about for the Orbiter Bus Route?

19. We are done with linked lists  Next 2 weeks- Stacks and Queues  Applicatio of stacks and queus

20. Reminders  All supervised exercises (1,2,3 and 4?)for July and August are due on 16 th Aug 40%  1 st unsupervised exercise (practical laboratory test) will be on 18 th Aug (Fri) 60%