1. TA: Nouf Al-Harbi nouf200@hotmail.com
Data Structures LAB 3
TA: Nouf Al-Harbi

2. Data structures lab 3
Sorted List

3. objectives By the end of this lab you will be able to :
Implement Sorted List Class with all its operations
Sorted List

4. Sorted List
List elements are in an order that is sorted in some way -- either numerically or alphabetically by the elements themselves, or by a component of the element (called a KEY member) .
Sorted List

5. Sorted List Example .. Implement Sorted List of 10 integer elements

6. SortedType class (data & methods members)
3 data members
Info
Array of 10 elements
Actual data of list
Length
Determines the length of list
Ranges between 0 (No elements and 10 (max number of elements)
CurrentPos
As an index
Ranges between -1 (prior to 1st element )and the length - 1(points to the last element)
Private data:
length
info [ 0 ]
[ 1 ]
[ 2 ]
[ 9 ]
currentPos
Sorted List

7. SortedType class (data & methods members)
Constructor
MakeEmpty
Private data:
length
info [ 0 ]
[ 1 ]
[ 2 ]
[ 9 ]
currentPos
InsertItem
Transformers
change state
DeleteItem
IsFull
Observers
Observe state
LengthIs
RetrieveItem
ResetList
Iterators
Process All
GetNextItem
Sorted List

8. Implementing Sorted Class
the class declaration is placed in one file (header file)  Sorted.h
the implementation of all the methods is put in another fileSorted.cpp
the Main function is put in another file
 SortedList.cpp
Foe each Sorted.cpp & SortedList we should inclusde Sorted.h file
#include “Sorted. h”
Sorted List

9. Implementing Sorted Class
1- class declaration
Sorted.h
Sorted List

10. Sorted.h // SPECIFICATION FILE ( Sorted.h ) const MAX_ELEMENTS=10;
class SortedType // declares a class data type {
public: // 8 public member functions
SortedType();
void MakeEmpty ( ) ;
bool IsFull ( ) const ;
int LengthIs ( ) const ; // returns length of list
bool RetrieveItem ( int item ) ;
void InsertItem ( int item ) ;
void DeleteItem ( int item ) ;
void ResetList ( );
int GetNextItem ( ) ;
private: // 3 private data members
int info[MAX_ELEMENTS] ;
int currentPos ;
int length;
} ;
Sorted List

11. Implementing Sorted Class
2- implementation of all the methods Sorted.cpp
Sorted List

12. SortedType Counstructor
SortedType::SortedType() {
length = 0; }
Sorted List

13. MakeEmpty Method void SortedType::MakeEmpty ( ) { length = 0 ; }
Sorted List

14. Inside constant functions we can’t change data values
IsFull Method
IsFull
Full  True
Not full  false
Inside constant functions we can’t change data values
bool SortedType::IsFull ( ) const {
return (length == MAX_ITEMS) ; }
Sorted List

15. LengthIs Method LengthIs int SortedType::LengthIs ( ) const {
Length of the list
int SortedType::LengthIs ( ) const {
return length ; }
Sorted List

16. ResetList Method void SortedType::ResetList ( ) { currentPos = -1 ; }
Sorted List

17. The item that follows the current item
GetNextItem Method
GetNextItem
The item that follows the current item
int SortedType::GetNextItem ( ) {
int item;
currentPos++;
item = info[currentPos];
return item ; }
Sorted List

18. The item that will be inserted
InsertItem Method
InsertItem
The item that will be inserted
Insert Item algorithm :
Find proper location for the new element in the sorted list.
Create space for the new element by moving down all the list elements that will follow it.
Put the new element in the list.
Increment length.

19. InsertItem Method

20. The item that will be deleted
DeleteItem Method
DeleteItem
The item that will be deleted
Delete Item algorithm:
Find the location of the element to be deleted from the sorted list.
Eliminate space occupied by the item being deleted by moving up all the list elements that follow it.
Decrement length

21. The item that will be deleted
DeleteItem Method
DeleteItem
The item that will be deleted

22. The item that will be searched for
RetrieveItem Method
RetrieveItem
The item that will be searched for
Found  true
Not found  false
Since the list is sorted, we can improve the search operation
So we don’t have to look at every element
By using what’s called
Binary Search

23. Sorted List

24. Binary Search in a Sorted List:
Compare the searched for value to the middle array item
if value == middle
then quit. You've found it.
else if value < middle
then consider the sub list making up the first half of the array (before the middle item)
else if value > middle
then consider the sub list making up the last half of the array (after the middle item)
If you didn't find the value, repeat the search on the sub list.
You are done as soon as you
find the item
or whenever the sub list that you are supposed to search is empty.
Sorted List

25. Binary Search Example 120<59 ? NO 120>59 ? YES  first = 0
Searching 120… 12 48 55 58 59 78 99
120
122
154 9 8 7 6 5 4 3 2 1
first
midPoint
last
120<59 ? NO
120>59 ?
YES 
first = 0
last = 9
midPoint = (0 + 9) / 2 = 4

26. Binary Search Example first = 5 last = 9 midPoint = (5 + 9) / 2 = 7
Searching 120… 12 48 55 58 59 78 99
120
122
154 9 8 7 6 5 4 3 2 1
first
midPoint
last
120< 120 NO
120> 120
120=120 ?
YES 
first = 5
last = 9
midPoint = (5 + 9) / 2 = 7
Stoop searching

27. 49< 59 YES  Binary Search Example first = 0 last = 9
Searching 49… 12 48 55 58 59 78 99
120
122
154 9 8 7 6 5 4 3 2 1
first
midPoint
last
49< 59
YES 
first = 0
last = 9
midPoint = (0 + 9) / 2 = 4

28. 49<48? NO 49>48? YES  Binary Search Example first = 0 last = 3
Searching 49… 12 48 55 58 59 78 99
120
122
154 9 8 7 6 5 4 3 2 1
first
midPoint
last
49<48? NO
49>48?
YES 
first = 0
last = 3
midPoint = (0 + 3) / 2 = 1

29. 49<55 ? NO 49>55 ? YES  Binary Search Example first = 2
Searching 49… 12 48 55 58 59 78 99
120
122
154 9 8 7 6 5 4 3 2 1
first
last
midPoint
49<55 ? NO
49>55 ?
YES 
first = 2
last = 3
midPoint = (2 + 3) / 2 = 2

30. Binary Search Example first = 2 last = 1
Searching 49…
not found 12 48 55 58 59 78 99
120
122
154 9 8 7 6 5 4 3 2 1
last
first
first = 2
last = 1
(first > last) => item not found

31. RetrieveItem Method

32. Implementing Sorted Class
3- Main function
SortedList.cpp
Sorted List

33. In Main function ..
Create an sorted List using Array Implementation to store the following integer numbers
2,3,4,8,9,12,14,23,33,50
Display the elements in the list
Retrieve the element 8 from the list
Retrieve the element 12 from the list
Ask about the length of the list
Ask whether the list is full or not
delete 2 and then 12 from the list
Delete 33 from the list
Sorted List