Chapter 5: linked list data structure

1. DATA STRUCTURE
Chapter 5: Linked List
Prepared & Presented by
Mr. Mahmoud R. Alfarra
2011-2012
College of Science & Technology
Dep. Of Computer Science & IT
BCs of Information Technology
http://mfarra.cst.ps

2. Out Line
 Self- Referential class
 What is Linked List?
 Insert & delete elements
 Print data
 Sorting data
 Search about data
 Collection of linked list
2

3. Self- Referential class
 Self- referential class is a class which contains
an object of it self.
 These concept uses to link objects with others.
3
class Node {
private int data;
private Node next;
public Node( int d )
{
// some code
} }
next object is an
object of Node
class, so this class
is a self referential
class

4. What is linked list ?
4
‫البيانات‬ ‫تراكيب‬ ‫مساق‬
‫إعداد‬ ‫العلمية‬ ‫المادة‬
/
‫أ‬
.
‫ا‬ َّ‫الفــر‬ ‫رفيق‬ ‫محمود‬
 A linked list is a collection of class objects
called nodes.
 Each node is linked to its successor node in
the list using a reference to the successor
node.
 A node is made up of a field for storing data
and the field for the node reference.
 The reference to another node is called a link.

5. Ahmad
25 year
Developer
Elements of list ?
5
 A list or linked list composed of number of
objects of a class, if you want to develop a list
of employees, you will insert many objects of
employees to your list, and so on …
Ali
28 year
Lecturer
Ola
27 year
Designer
....

6. Application: List of cars
6
Car
Class
ListCar
Class
CarSystem
Class
In this class we
will create an
object of ListCar
class, and then
manipulates the
list using all
operations.
The class of
linked list
members and
operation, this
class simulate the
list of any thing,
the object of this
class will be
created and used
in the class of
CarSystem.
A self referential
class called Car,
contains the
attributes and
behavior of any
car.
1
2
3

7. 1- Class Car
7
1. class Car
2. {
3. public int id;
4. public String location;
5. public String type;
6. public Car next;
7. public Car()
8. {
9. id = 0;
10. location = "Gaza";
11. type = "Private";
12. }
13. }

8. 2- class ListCar
8
1. class ListCar
2. {
3. private int length ; // instance variable to count number of elements in
the list
4. public Car head; // Object will point to the first element in the list
5. public ListCar()
6. {
7. lenght = 0;
8. head = null; // initially the head points to nothing
9. }
10. // Here the manipulated operation will be developed
11. }

9. Create object of List Car
9
1. static void Main(string[] args)
2. {
3. ListCar list1 = new ListCar();
4. }
 This objet of list will be manipulated using the
operations.

10. Insert at the first position
Data 1
Head
Data 2 Data 3 Data n
…..
null
New
data
1
2

11. Insert at the first position
11
1. class ListCar {
2. private int lenght ;
3. public Car head;
4. public ListCar() {
5. lenght = 0;
6. head = null; }
7. public void addAtFront(Car inserted) {
8. Car newc = new Car();
9. newc = inserted;
10. newc.next = head;
11. lenght++;
12. head = newc; }
13. }
Please Note that: all codes in the
PPT files of this course are not
completely, so you must depend
on the practical files.
The current codes are only to
explain the main idea

12. Insert at the last position
Data 1
Front
Data 2 Data 3 Data n
…..
null
New
data
2
null
1
Back
X 1
Back
X 1
Back
X 1
Back
X

13. Insert at the last position
13
‫البيانات‬ ‫تراكيب‬ ‫مساق‬
‫إعداد‬ ‫العلمية‬ ‫المادة‬
/
‫أ‬
.
‫ا‬ َّ‫الفــر‬ ‫رفيق‬ ‫محمود‬
1. class ListCar {
2. ….
3. public void addAtFront(Car inserted) {
4. … }
5. public void addAtback(Car inserted) {
6. Car newc = new Car();
7. Car back = head;
8. while (back.next != null)
9. back = back.next;
10. back.next = newc;
11. newc.next = null;
12. length ++;
13. }
14. }
If the list is empty?
What will be do?

14. Delete the first elements
Data 1
Head
Data 2 Data 3 Data n
…..
null
X

15. Delete the first elements
15
‫البيانات‬ ‫تراكيب‬ ‫مساق‬
‫إعداد‬ ‫العلمية‬ ‫المادة‬
/
‫أ‬
.
‫ا‬ َّ‫الفــر‬ ‫رفيق‬ ‫محمود‬
1. class ListCar {
2. ….
3. public void addAtFront(Car inserted) {
4. … }
5. public void addAtback(Car inserted) {
6. … }
7. public void RemoveFromFront()
8. {
9. head = head.next;
10. lenght--;
11. }
12.}

16. Delete the last elements
Data 1
Front
Data 2 Data 3 Data n
…..
null
Back
current
×
1
2

17. Delete the last elements
17
‫البيانات‬ ‫تراكيب‬ ‫مساق‬
‫إعداد‬ ‫العلمية‬ ‫المادة‬
/
‫أ‬
.
‫ا‬ َّ‫الفــر‬ ‫رفيق‬ ‫محمود‬
1. class ListCar {
2. ….
3. public void addAtFront(Car inserted) { … }
4. public void addAtback(Car inserted) { … }
5. public void RemoveFromFront() { … }
6. public void RemoveFromback() {
7. Car current = head;
8. Car back = head.next;
9. while (back.next != null) {
10. back = back.next;
11. current = current.next; }
12. current.next = null;
13. lenght--; }
14.}

18. Insert a new element at
position k
Data 1
Head
Data 2 Data 3 Data n
…..
null
New
data
1
Will be inserted at position 2 (the third element)
0 1 2 n
2
×
current

19. Insert a new element at
position k
19
‫البيانات‬ ‫تراكيب‬ ‫مساق‬
‫إعداد‬ ‫العلمية‬ ‫المادة‬
/
‫أ‬
.
‫ا‬ َّ‫الفــر‬ ‫رفيق‬ ‫محمود‬
1. class ListCar {
2. ….
3. public void RemoveFromback() { …. }
4. public void addAtPosition(Car inserted, int position) {
5. Car current = head;
6. Car newc = inserted;
7. int counter =0;
8. while (counter < position) {
9. current = current.next;
10. counter++; }
11. newc.next = current.next;
12. current.next = newc;
13. lenght++; }
14.}

20. Insert a new element based on an
order
Data 1
Head
Data 2 Data 3 Data n
…..
null
New
data
1
Example: Will be inserted after the value x
0 1 2 n
2
×
current
Front

21. Insert a new element based on an
order
21
‫البيانات‬ ‫تراكيب‬ ‫مساق‬
‫إعداد‬ ‫العلمية‬ ‫المادة‬
/
‫أ‬
.
‫ا‬ َّ‫الفــر‬ ‫رفيق‬ ‫محمود‬
1. class ListCar {
2. ….
3. public void addAtPosition(Car inserted, int position) { … }
4. public void addAtvalue(Car inserted, int value) {
5. Car current = head;
6. Car front = head;
7. Car newc = inserted;
8. while (current.value < value) {
9. front = current;
10. current = current.next; }
11. newc.next = current;
12. front.next = newc;
13. lenght++; }
14.}
•The new element will be
inserted in its right position
based on its value.
• Note that the list is ordered.

22. Delete an element from
position
Data 1
Head
Data k-
1
Data k Data n
null
Current
Data
k+1
1
× ×
Front

23. Delete an element from
position
23
‫البيانات‬ ‫تراكيب‬ ‫مساق‬
‫إعداد‬ ‫العلمية‬ ‫المادة‬
/
‫أ‬
.
‫ا‬ َّ‫الفــر‬ ‫رفيق‬ ‫محمود‬
1. class ListCar {
2. ….
3. public void RemovefromPosition(int position) {
4. Car current = head;
5. Car front = head;
6. int counter = 0;
7. while (counter < position) {
8. current = front;
9. front = front.next;
10. counter++; }
11. current.next = front.next;
12. lenght--; }
13.}
Practice 1: re-
code it to delete
the node which
has value x

24. Print the data …
24
1. class ListCar {
2. ….
3. public void PrintData() {
4. Car current = head;
5. Console.WriteLine("The Data of List are");
6. int counter = 1;
7. while (current != null) {
8. Console.WriteLine("The Data of element # "+counter);
9. Console.WriteLine("=======================");
10. Console.WriteLine("ID " + current.id);
11. Console.WriteLine("Location " + current.location);
12. Console.WriteLine("Type " + current.type);
13. Console.WriteLine("=======================");
14. current = current.next;
15. counter++; }
16. }}

25. Sort linked List by swapping objects
(bubble)
Data 1
Head
Data k-
1
Data k Data n
null
Data
k+1
Current
b
c d
Second
e
Temp
1
a
2
3
Data 1
Head
Data k Data k-1 Data n
null
Data
k+1
b c d e
a
4

26. Sort linked List by swapping objects
(bubble)
Data 1
Head
Data k-
1
Data k Data n
null
Data
k+1
Current
b
c d
Second
e
Temp
1
a
2
3
4
Node current = head;
Node temp;
for (int i = 0; i < lenght; i++) {
Car current = head;
while (current.Next != null) {
temp.data = current.Next.data;
current.Next.Value = current.Value;
current.Value = temp;
current = current.Next.Next; }
}

27. Sort linked List by swapping values
(bubble)
Data 1
Head
Data k-
1
Data k Data n
null
Data
k+1
Current
b
c d e
a
Front
Tempalue = Current.value;
Current.value = front.value;
Front.value = tempvalue;
. . .

28. Sort linked List by swapping values
(bubble)
28
‫البيانات‬ ‫تراكيب‬ ‫مساق‬
‫إعداد‬ ‫العلمية‬ ‫المادة‬
/
‫أ‬
.
‫ا‬ َّ‫الفــر‬ ‫رفيق‬ ‫محمود‬
1. class ListCar {
2. public void bubSort() {
3. for (int i = 0; i < lenght; i++) {
4. Car current = head;
5. while (current.next != null) {
6. if (current.value > current.next.value) {
7. int TempValue = current.value;
8. int TempId = current.id;
9. String TempLocation = current.location;
10. current.value = current.next.value;
11. current.id = current.next.id;
12. current.location = current.next.location;
13. current.next.value = TempValue;
14. current.next.id = TempId;
15. current.next.location = TempLocation; }
16. current = current.next; } } }
17. }

29. Search about data !!
1. class ListCar {
2. public Car Find(int WantedVlaue )
3. {
4. Car current = head;
5. int flag = -1;
6. while (current != null) {
7. if (current.value == WantedVlaue) {
8. flag = 1;
9. break; }
10. current = current.next; }
11. if (flag == 1)
12. return current;
13. else
14. return null; }
15. }

30. Collection of linked list
30
 C# contains the collection of linked list in the
name space called:
Namespace: System.Collections.Generic
 It has a full package of methods and members
to manage its data.
Case Study :using the reference
book, write a completed
application to simulate the linked
list of PCs.

31. Thank You …
31
Remember that: question is the key of knowledge

32. Ahl Eljanna 

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‫َّق‬‫ت‬ُ
‫ْم‬‫ل‬‫ا‬ َّ
‫ن‬ِ‫إ‬
(
)::
ٍ
‫ون‬ُ‫ي‬ُ‫ع‬َ
‫و‬ ٍ
‫َّات‬‫ن‬َ
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::(
)
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‫ني‬ِ‫ل‬ِ‫ب‬‫ا‬َ
‫ق‬َ‫ت‬ُ
‫م‬ ٍ
‫ق‬
)::(
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)::(
32