1. CS 302 - Data Structures Chapter 8 Lists Mehmet H Gunes
Modified from authors’ slides

2. Contents Specifying the ADT List Using the List Operations
An Interface Template for the ADT List
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

3. Specifying the ADT List
A grocery list
You reference list
items by their
position
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

4. ADT List Operations Test whether a list is empty.
Get number of entries on a list.
Insert entry at given position on list.
Remove entry at given position from list.
Remove all entries from list.
Look at (get) entry at given position on list.
Replace (set) entry at given position on list.
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

5. ADT List Operations UML diagram for the ADT list
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

6. Abstract Data Type: LIST
Data : A finite number of objects
Not necessarily distinct
Having the same data type
Ordered by their positions determined by client.
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

7. Abstract Data Type: LIST
Operations
isEmpty()
getLength()
insert(newPosition, newEntry)
remove(position)
clear()
getEntry(position)
setEntry(position, newEntry)
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

8. Axioms for the ADT List (new List()).isEmpty() = true
(new List()).getLength() = 0
aList.getLength() = (aList.insert(i, x)). getLength() - 1
aList.getLength() = (aList.remove(i)). getLength() + 1
(aList.insert(i, item)).isEmpty() = false
(new List()).remove(i) = false
(aList.insert(i, x)).remove(i) = aList
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

9. Axioms for the ADT List (new List()).getEntry(i) = error
(aList.insert(i, x)).getEntry(i) = x
aList.getEntry(i) = (aList.insert(i, x)). getEntry(i + 1)
aList.getEntry(i + 1) = (aList.remove(i)). getEntry(i)
(new List()).setEntry(i, x) = error
(aList.setEntry(i, x)).getEntry(i) = x
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

10. Using the List Operations
Displaying the items on a list independent of the implementation
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

11. Using the List Operations
Replacing an item.
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

12. Using the List Operations
Pseudocode statements place names in an alphabetical list
View Interface Template for the ADT List, Listing 8-1
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

13. List Implementations
Chapter 9

14. Contents An Array-Based Implementation of the ADT List
A Link-Based Implementation of the ADT List
Comparing Implementations
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

15. Array-Based Implementation of ADT List
Recall list operations in UML form
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

16. An array-based implementation of the ADT list
The Header File
View header file for the class ArrayList, Listing 9-1
An array-based implementation of the ADT list
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

17. The Implementation File
Constructor
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

18. The Implementation File
isEmpty tests whether itemCount is zero
getLength simply returns the value of itemCount :
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

19. The Implementation File
Definition of the method insert
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

20. The Implementation File
Shifting items for insertion: (a) the list before the insertion;
(b) copy items to produce room at position 3; (c) the result
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

21. The Implementation File
The method getEntry.
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

22. The Implementation File
Testing core group of methods
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

23. The Implementation File
The method setEntry
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

24. The Implementation File
The definition of remove
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

25. The Implementation File
(a) Deletion can cause a gap; (b) shift items to prevent a gap at position 3; (c) the result
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

26. The Implementation File
The method clear.
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

27. A Link-Based Implementation of the ADT List
Data Structures and Problem Solving with C++: Walls and Mirrors, Carrano and Henry, © 2013

28. C++ Data Structures Nell Dale

29. Sorted and Unsorted Lists
Elements are placed into the list in
no particular order.
SORTED LIST
List elements are in an order that is sorted in
some way
either numerically,
alphabetically by the elements themselves, or by a component of the element
called a KEY member

30. Complexities
the order of the operation that determines if an item is in
a list in a sorted, array-based implementation
a list in an unsorted, array-based implementation
a list in a sorted, linked implementation
a list in an unsorted, linked implementation
O(log N)
O(N)
O(N)
O(N)

31. Allocation of memory
STATIC
ALLOCATION
Static allocation is the allocation of memory space at compile time.
DYNAMIC
ALLOCATION
Dynamic allocation is the allocation of memory space at run time by using operator new. 31

32. 3 Kinds of Program Data
STATIC DATA: memory allocation exists throughout execution of program.
static long SeedValue;
AUTOMATIC DATA: automatically created at function entry, resides in activation frame of the function, and is destroyed when returning from function.
DYNAMIC DATA: explicitly allocated and deallocated during program execution by C++ instructions written by programmer using unary operators new and delete 32

33. Dynamic Array Allocation
char *ptr; // ptr is a pointer variable that
// can hold the address of a char
ptr = new char[ 5 ];
// dynamically, during run time, allocates
// memory for 5 characters and places into
// the contents of ptr their beginning address
6000
6000
ptr 33

34. Dynamic Array Allocation
char *ptr ;
ptr = new char[ 5 ];
strcpy( ptr, “Bye” );
ptr[ 1 ] = ‘u’; // a pointer can be subscripted
std::cout << ptr[ 2] ;
6000
‘u’
6000
‘B’ ‘y’ ‘e’ ‘\0’
ptr 34

35. InsertItem algorithm for Sorted Linked List
Find proper position for the new element in the sorted list using two pointers predLoc and location, where predLoc trails behind location.
Obtain a node for insertion and place item in it.
Insert the node by adjusting pointers.
Increment length. 35

36. The Inchworm Effect 36

37. Why is a destructor needed?
When a local list variable goes out of scope, the memory space for data member listPtr is deallocated. But the nodes to which listPtr points are not deallocated. A class destructor is used to deallocate the dynamic memory pointed to by the data member. 37 37

38. What is a Circular Linked List?
A circular linked list is a list in which every node has a successor; the “last” element is succeeded by the “first” element.

39. External Pointer to the Last Node

40. What is a Doubly Linked List?
A doubly linked list is a list in which each node is linked to both its successor and its predecessor.

41. Linking the New Node into the List

42. Deleting from a Doubly Linked List
What are the advantages of a circular doubly linked list?

43. What are Header and Trailer Nodes?
A Header Node is a node at the beginning of a list that contains a key value smaller than any possible key.
A Trailer Node is a node at the end of a list that contains a key larger than any possible key.
Both header and trailer are placeholding nodes used to simplify list processing.

44. A linked list in static storage ?
A Linked List as an Array of Records

45. A Sorted list Stored in an Array of Nodes

46. An Array with Linked List of Values and Free Space

47. An Array with Three Lists (Including the Free List)