1. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 1 Brief Review of ADTs and Class Implementation Chapter 4-8

2. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 2 Contents 1.ADT? (ch. 2) 2.Classes (ch. 4) 3.List and its class implementation (ch. 6) 4.Stack and its class implementation (ch. 7) 5.Queue and its class implementation (ch. 8)

3. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 3 Objectives Review ADTs Review classes in C++ Review list with class implementation Review stack with class implementation Review Queue with class implementation

4. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 4 What is ADT? ADT = data items + operations on the data Implementation of ADT –Storage/data structures to store the data –Algorithms for the operations, i.e., how to do it

5. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 5 Structs and Classes Similarities Essentially the same syntax Both are used to model objects with multiple attributes (characteristics) –represented as data members –also called fields … or … –instance or attribute variables Thus, both are used to process non- homogeneous data sets.

6. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 6 Structs vs. Classes Differences No classes in C Members public by default Can be specified private Both structs and classes in C++ Structs can have members declared private Class members are private by default Can be specified public

7. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 7 Advantages in C++ (structs and Classes) C++ structs and classes model objects which have: –Attributes represented as data members –Operations represented as functions (or methods) Leads to object oriented programming –Objects are self contained –"I can do it myself" mentality –They do not pass a parameter to an external function

8. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 8 Class Declaration Syntax class ClassName { public: Declarations of public members private: Declarations of private members };

9. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 9 Designing a Class Data members normally placed in private: section of a class (information hiding) Function members usually in public: section (exported for external use) Typically public: section followed by private: –although not required by compiler –Actually nobody cares, at least for me

10. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 10 Class Libraries Class declarations placed in header file –Given.h extension –Contains data items and prototypes Implementation file –Same prefix name as header file –Given.cpp extension Programs which use this class library called client programs

11. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 11 Translating a Library

12. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 12 Example of User-Defined Time Class Now we create a Time class (page 150) –Actions done to Time object, done by the object itself Note interface for Time class object, Fig. 4.2 Fig. 4.2 –Data members private – inaccessible to users of the class –Information hiding

13. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 13 Constructors Understanding Constructors, p158-159 –Initialize data members –Optional: allocate memory Note constructor definition in Time.cpp example (p161) example Syntax ClassName::ClassName (parameter_list) : member_initializer_list { // body of constructor definition }

14. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 14 Constructors Results of default constructor Results of explicit-value constructor

15. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 15 Overloading Functions Note existence of multiple functions with the same name Time(); Time(unsigned initHours, unsigned initMinutes, char initAMPM); –Known as overloading Compiler compares numbers and types of arguments of overloaded functions –Checks the "signature" of the functions

16. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 16 Default Arguments Possible to specify default values for constructor arguments Time(unsigned initHours = 12, unsigned initMinutes = 0, char initAMPM = 'A'); Consider Time t1, t2(5), t3(6,30), t4(8,15,'P');

17. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 17 Copy Operations(p166) During initialization Time t = bedTime During Assignment t = midnight;

18. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 18 Overloading Operators Same symbol can be used more than one way Operator , function: operator  () Two cases –If  is a function member: a  b  a.operator  (b) –Otherwise, a  b  operator  (a,b) Operators: +,-,*,/ Operators: >

19. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 19 Overloading << void operator<<(ostream& out, const Time& t) ostream& operator<<(ostream& out, const Time& t) Question: which one is right? Why? See p170-171 See example p173: why need a member function to overload >?

20. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 20 Friend Functions Note use of two functions used for output –display() and operator<<() Possible to specify operator<<() as a "friend" function –Thus given "permission" to access private data elements Declaration in.h file (inside the class declaration with friend keyword) friend ostream & operator<<( ostream & out, const Time & t)

21. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 21 Friend Functions Definition in.cpp file ostream & operator<<( ostream & out, const Time & t) {out << t.myHours<<":" <<(t.myMinutes< 10? "0": "") <<t.myMinutes << ' '<<t.myAMorPM<<".M."; return out; } Note - a friend function not member function –not qualified with class name and :: –receives class object on which it operates as a parameter Author prefers not to use friend function Violates principle of information hiding Author prefers not to use friend function Violates principle of information hiding

22. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 22 Other Operations Advance OperationAdvance –Time object receives a number of hours and minutes –Advances itself by adding to myHours, myMinutes Relational Operators –Time object compares itself with another –Determines if it is less than the other

23. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 23 Redundant Declarations Note use of #include "Time.h" in –Time.cppTime.cpp –Client programClient program Causes "redeclaration" errors at compile time Solution is to use conditional compilation –Use #ifndef and #define and #endif compiler directives#ifndef and #define #endif

24. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 24 Pointers to Class Objects Possible to declare pointers to class objects Time * timePtr = &t; Access with timePtr->getMilTime() or (*timePtr).getMilTime()

25. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 25 The this Pointer Every class has a keyword, this –a pointer whose value is the address of the object –Value of *this would be the object itself

26. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 26 Exercises Implement a polynomial class in the form of ax+b, coefficients a and b are integers. –Constructor –Overload operator+ –Overload operator<<, do not use friend function.

27. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 27 Review for Last Class’s Example

28. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 28 Example for class “ax+b” //poly.h: header file #include #ifndef _POLY_H // avoid redundant declarations #define _POLY_H class Poly { private: int m_ca; //coefficient a int m_cb; public: Poly(int a, int b) : m_ca(a), m_cb(b) { }; //constructor void display(ostream& out) const; //for operator << overloading Poly operator+(const Poly& po); //overloading + }; //do not forget to put ; !!!! ostream& operator<<(ostream& out, const Poly& po); //overloading << #endif

29. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 29 Example: ax+b //poly.cpp: implementation file #include “poly.h” using namespace std; void Poly::display(ostream& out) const { out m_ca + po.m_ca; //what is “this”? Do we need it here? c.m_cb = m_cb + po.m_cb; return c; } ostream& operator<<(ostream& out, const Poly& po) { po.display(out); return out; }

30. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 30 To-do-list Review: class, overloading operators In-class Exercise –Operator “-” and “>>” overloading in last class example List implementations –Destructor –Copy constructor –Assignment operator

31. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 31 Lists Chapter 6

32. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 32 Chapter Contents 6.1 List as an ADT 6.2 An Array-Based Implementation of Lists 6.3 An array Based Implementation of Lists with Dynamic Allocation 6.4 Introduction to Linked Lists 6.5 A Pointer-Based Implementation of Linked Lists in C++

33. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 33 Chapter Objectives To study list as an ADT Build a static-array-based implementation of lists and note strengths, weaknesses Build a dynamic-array-based implementation of lists, noting strengths and weaknesses –See need for destructor, copy constructor, assignment methods Take first look at linked lists, note strengths, weaknesses Study pointer-based implementation of linked lists

34. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 34 Consider Every Day Lists Groceries to be purchased Job to-do list List of assignments for a course Dean's list Can you name some others??

35. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 35 Properties of Lists Can have a single element Can have no elements  empty! There can be lists of lists We will look at the list as an abstract data type –Homogeneous –Finite length –Sequential elements

36. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 36 Basic Operations Construct an empty list Determine whether or not empty Insert an element into the list Delete an element from the list Traverse (iterate through) the list to –Modify –Output –Search for a specific value –Copy or save –Rearrange

37. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 37 Designing a List Class Should contain at least the following function members –Constructor –empty() –insert() –delete() –display() Implementation involves –Defining data members –Defining function members from design phase

38. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 38 Array-Based Implementation of Lists An array is a viable choice for storing list elements –Element are sequential –It is a commonly available data type –Algorithm development is easy Normally sequential orderings of list elements match with array elements

39. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 39 Implementing Operations Constructor –Static array allocated at compile time. No need to allocate explicitly! Empty –Check if size == 0 –Traverse –Use a loop from 0 th element to size – 1 Insert –Shift elements to right of insertion point Delete –Shift elements back Also adjust size up or down

40. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 40 List Class with Static Array Must deal with issue of declaration of CAPACITY, p262 Use typedef mechanism typedef Some_Specific_Type ElementType ElementType array[CAPACITY]; For specific implementation of our class we simply fill in desired type for Some_Specific_Type

41. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 41 List Class with Static Array Can put typedef declaration inside or outside of class –Inside: must specify List::ElementType for reference to the type outside the class –Outside: now able to use the template mechanism (this will be our choice) Also specify the CAPACITY as a const –Also choose to declare outside class

42. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 42 List Class Example, p262 Declaration file, Fig. 6.1A6.1A –Note use of typedef mechanism outside the class –This example good for a list of int Definition, implementation Fig. 6.1B6.1B –Note considerable steps required for insert() and erase() functions insert() erase() Program to test the class, Fig 6.1C6.1C

43. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 43 List Class with Static Array - Problems Stuck with "one size fits all" –Could be wasting space –Could run out of space Better to have instantiation of specific list specify what the capacity should be Thus we consider creating a List class with dynamically-allocated array

44. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 44 Dynamic-Allocation for List Class Changes required in data members –Eliminate const declaration for CAPACITY –Add data member to store capacity specified by client program –Change array data member to a pointer –Constructor requires considerable change Little or no changes required for –empty() –display() –erase() –insert()

45. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 45 Dynamic-Allocation for List Class Note data changes in Fig. 6.2A, List.h,p270Fig. 6.2A Note implementation file Fig. 6.2B, List.cppFig. 6.2B –Changes to constructor –Addition of other functions to deal with dynamically allocated memory Note testing of various features in Fig. 6.2C, the demo programFig. 6.2C

46. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 46 Dynamic-Allocation for List Class Now possible to specify different sized lists cin >> maxListSize; List aList1 (maxListSize); List aList2 (500);

47. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 47 New Functions Needed Destructor –When class object goes out of scope the pointer to the dynamically allocated memory is reclaimed automatically –The dynamically allocated memory is not –The destructor reclaims dynamically allocated memory

48. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 48 New Functions Needed Copy Constructor – makes a "deep copy" of an object, p278Copy Constructor –When argument passed as value parameter –When function returns a local object –When temporary storage of object needed –When object initialized by another in a declaration If copy is not made, observe results (aliasing problem, "shallow" copy)

49. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 49 Copy Constructor, p280 The parameter must be a reference parameter and should be a const reference parameter as well –If value parameter, infinite chain of function calls!!! –List(const List& org) Work to be done –Allocate memory –Ensure deep copy by element-by-element copy

50. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 50 New Functions Needed Assignment operator –Default assignment operator makes shallow copy –Can cause memory leak, previous dynamically- allocated memory has nothing pointing to it

51. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 51 Assignment Operator Must be member function, a=b  a.operator=(b) Return const reference to the object –const ClassName& operator=(const ClassName& right) First check if self-assignment: otherwise having problem in “list1 = list1”; Avoid memory leak by releasing previous allocated memory Ensure deep copy

52. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 52 Difference between Copy constructor and Assignment Operator Function return value? Self assignment check? Memory leak? Deep copy?

53. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 53 Notes on Class Design If a class allocates memory at run time using the new, then a it should provide … A destructor A copy constructor (by complier to make a copy) An assignment operator (by programmer) Note Fig. 6.3 which exercises constructors and destructor, p263Fig. 6.3

54. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 54 Future Improvements to Our List Class Problem 1: Array used has fixed capacity Solution: –If larger array needed during program execution –Allocate, copy smaller array to the new one Problem 2: Class bound to one type at a time Solution: –Create multiple List classes with differing names –Use class template

55. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 55 Recall Inefficiency of Array-Implemented List insert() and erase() functions inefficient for dynamic lists –Those that change frequently –Those with many insertions and deletions So … We look for an alternative implementation.

56. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 56 Linked List For the array-based implementation: 1.First element is at location 0 2.Successor of item at location i is at location i + 1 3.End is at location size – 1 Fix: 1.Remove requirement that list elements be stored in consecutive location. 2.But then need a "link" that connects each element to its successor Linked Lists !!

57. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 57 Linked List Linked list nodes contain –Data part – stores an element of the list –Next part – stores link/pointer to next element (when no next element, null value)

58. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 58 Linked Lists Operations Construction: first = null_value ; Empty: first == null_value ? Traverse –Initialize a variable ptr to point to first node –Process data where ptr points

59. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 59 Linked Lists Operations Traverse (ctd) –set ptr = ptr->next, process ptr->data –Continue until ptr == null

60. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 60 Operations: Insertion Insertion –To insert 20 after 17 –Need address of item before point of insertion –predptr points to the node containing 17 –Get a new node pointed to by newptr and store 20 in it –Set the next pointer of this new node equal to the next pointer in its predecessor, thus making it point to its successor. –Reset the next pointer of its predecessor to point to this new node 20 newptr predptr

61. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 61 Operations: Insertion Note: insertion also works at end of list –pointer member of new node set to null Insertion at the beginning of the list –predptr must be set to first –pointer member of newptr set to that value –first set to value of newptr  Note: In all cases, no shifting of list elements is required !

62. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 62 Operations: Deletion Delete node containing 22 from list. –Suppose ptr points to the node to be deleted –predptr points to its predecessor (the 20) Do a bypass operation : –Set the next pointer in the predecessor to point to the successor of the node to be deleted –Deallocate the node being deleted. predptr ptr To free space

63. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 63 Linked Lists - Advantages Access any item as long as external link to first item maintained Insert new item without shifting Delete existing item without shifting Can expand/contract as necessary

64. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 64 Linked Lists - Disadvantages Overhead of links: –used only internally, pure overhead If dynamic, must provide –destructor –copy constructor No longer have direct access to each element of the list –Many sorting algorithms need direct access –Binary search needs direct access Access of n th item now less efficient –must go through first element, and then second, and then third, etc.

65. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 65 Linked Lists - Disadvantages List-processing algorithms that require fast access to each element cannot be done as efficiently with linked lists. Consider adding an element at the end of the list ArrayLinked List a[size++] = value; Get a new node; set data part = value next part = null_value If list is empty Set first to point to new node. Else Traverse list to find last node Set next part of last node to point to new node. This is the inefficient part

66. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 66 Using C++ Pointers and Classes To Implement Nodes class Node { public: DataType data; Node * next; }; Note: The definition of a Node is recursive –(or self-referential) It uses the name Node in its definition The next member is defined as a pointer to a Node

67. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 67 Working with Nodes Declaring pointers Node * ptr; or typedef Node * NodePointer; NodePointer ptr; Allocate and deallocate ptr = new Node;delete ptr; Access the data and next part of node (*ptr).data and (*ptr).next or ptr->data and ptr->next

68. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 68 Working with Nodes Note data members are public This class declaration will be placed inside another class declaration for List (private section), p296 The data members data and next of struct Node will be public inside the class –will accessible to the member and friend functions of List –will be private outside the class class Node { public: DataType data; Node * next; };

69. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 69 typedef int ElementType; class List { private: class Node { public: ElementType data; Node * next; }; typedef Node * NodePointer;... Class List data is public inside class Node class Node is private inside List data is public inside class Node class Node is private inside List

70. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 70 Data Members for Linked-List Implementation A linked list will be characterized by: –A pointer to the first node in the list. –Each node contains a pointer to the next node in the list –The last node contains a null pointer As a variation first may –be a structure – also contain a count of the elements in the list

71. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 71 Function Members for Linked-List Implementation Constructor –Make first a null pointer and –set mySize to 0 Destructor –Nodes are dynamically allocated by new –Default destructor will not specify the delete –All the nodes from that point on would be "marooned memory" –A destructor must be explicitly implemented to do the delete 0

72. Nyhoff, ADTs, Data Structures and Problem Solving with C++, Second Edition, © 2005 Pearson Education, Inc. All rights reserved. 0-13-140909-3 72 Function Members for Linked-List Implementation Copy constructor for deep copy –By default, when a copy is made of a List object, it only gets the head pointer –Copy constructor will make a new linked list of nodes to which copy will point Shallow Copy