Data structure

1. MINISTRY OF EDUCATION & HIGHER EDUCATION COLLEGE OF SCIENCE AND TECHNOLOGY KHANYOUNIS- PALESTINE Using C# Information Technology , 3’rd Semester Data structure Lecture 7: Linked List(2) Presented By: Mahmoud Rafeek Alfarra

2. Outline • Add item in the front of linked list • Add item in the n’th place of linked list • Print the data of linked list • Delete item from the back of the linked list • Delete item from the front of the linked list • Delete the n’th item from the linked list • Emank X Mezank !!

3. Add item in the front of linked list • Add the new item in the front, mean that the new item will be pointed to the first one. 1 Head Back Data 1 Data 2 Data 3 Data n ….. null New data Presented & Prepared by: Mahmoud R. Alfarra

4. Add item in the front of linked list New.Next = first; Front = new; Size ++ 1 Head Back Data 1 Data 2 Data 3 Data n ….. null New data Presented & Prepared by: Mahmoud R. Alfarra

5. Add item in the n’th place of linked list • Add the new item in the n’th place, mean that the new item will be pointed to the (n)’th node and then the (n-1)’th node will be pointed to new node. Head 1 Back × Data 1 Data 2 Data 3 Data n ….. 0 1 2 n null 2 New data New node will be inserted at the 3’rd place Presented & Prepared by: Mahmoud R. Alfarra

6. Add item in the n’th place of linked list New.Next = n’th_node; (n-1)’th_node.next = new; Size ++ Head 1 Back × Data 1 Data 2 Data 3 Data n ….. 0 1 2 n null 2 New data New node will be inserted at the 3’rd place Presented & Prepared by: Mahmoud R. Alfarra

7. Print the data of the linked list 7 • Once a list exists, the user can explorer it. • One of the operations performed on linked List is to prints its data. • To do this, you can declare a method that examines the head of the list is not pointing to null. • Using for loop … Item Current = Head; for(int i = 0; Current != null; i++) Print current.data; Current = Current.Next; Presented & Prepared by: Mahmoud R. Alfarra

8. Example (Linked List of cars) 8 Build the item list of car: Which is a class of car Contains the car’s data Contains a variable of car to point to the next node class Car { public string name; public Car next; } 1 Presented & Prepared by: Mahmoud R. Alfarra

9. Example (Linked List of cars) 9 Build the list of car : Which is a management class contains Length of list which begins as 0 A variable of car as the pointer of each node and begins as null All the operations class LinkedCar { private int length ; public Car head; public LinkedCar() { lenght = 0; head = null; }} 2 Presented & Prepared by: Mahmoud R. Alfarra

10. Example (operations on Linked List) 10 Add a new car to the linked list in the front In the class of management (LinkedCar), we declare all the operations as add, remove, sort, … 3 public void addAtFront(Car inserted) { Car newc = new Car (); newc = inserted; newc.next = head; lenght++; head = newc; } HW 7.1 Write the methods to add a new elements in the n’th position and as the last node Presented & Prepared by: Mahmoud R. Alfarra

11. Example (operations on Linked List) 11 Print the information of the cars in the LinkedList 4 public void printCarData() { Car current = head; for (int i =0 ; current != null; i++) { Console.WriteLine("The name is "+ current.name); current = current.next; } } HW 7.2 Write the methods to print the data of i’th node Presented & Prepared by: Mahmoud R. Alfarra

12. Example (create an object of LinkedCar) 12 Create a linkedlist of cars The class of management (LinkedCar) is just a class. so, need to create object to perform the operations … static void Main(string[ ] args) { LinkedCar list1 = new LinkedCar(); Car car1 = new Car(); car1.name = "Mahmoud"; list1.addAtFront(car1); Car car2 = new Car(); car2.name = "Ali"; list1.addAtFront(car2); list1.printCarData(); Console.Read(); } 5 Presented & Prepared by: Mahmoud R. Alfarra

13. Home Work 13 HW 7.3 Re-write the previous example using the windows application, as the above figure Presented & Prepared by: Mahmoud R. Alfarra

14. Retrieve data from the linked list 14 • Current = Head • For (int i = 0; Current != null ; i++) • Current = Current.Next; • return current.data Back Current 4 Current Current Head 2 Current 3 1 Data 1 Data k-1 Data k Data n Data k+1 null Presented & Prepared by: Mahmoud R. Alfarra

15. Delete an item from the linked list 15 • Deleting an item consists of removing it from the list. • There are two main types of deletion you can perform on a list. • You can simply ask the class to delete an item. In this case, it is usually the item at the end that gets deleted. • Another technique used to delete an item consists of specifying the position of the item to be deleted. Presented & Prepared by: Mahmoud R. Alfarra

16. Delete item from the back of the linked list 16 • (Last-1)node.next = null • Back = (Last-1)node × Back Head × 2 ….. Data 1 Data 2 Data n-1 Data n 1 null Presented & Prepared by: Mahmoud R. Alfarra

17. Delete item from the front of the linked list 17 • Current = head.next • Head = current • Size -- Back Current Head × ….. Data 1 Data 2 Data n-1 Data n null Presented & Prepared by: Mahmoud R. Alfarra

18. Delete the k’th item from the linked list 18 • current = position(k-1) • current.next = position(k+1) • Size -- 1 Back Head × × Data 1 Data k-1 Data k Data n Data k+1 null HW 7.4 Write the methods to perform the deletion operations Presented & Prepared by: Mahmoud R. Alfarra

19. Search about data in the linked list 19 • Wanted data • Current = Head • For (int i = 0; Current != null && current.data != wanted ; i++) • If (current.data == wanted) • return i • break • Current = Current.Next; HW 7.4 Write the methods to perform the search operations Presented & Prepared by: Mahmoud R. Alfarra

20. Emank X Mezank !! أخي أنت حرٌّ وراء السدود ..... أخي أنت حرٌّ بتلك القيود إذا كنـت بالله مستعصمـا .... فماذا يضيرك كيد العبيد؟!!

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