1. Data Structures and Algorithms in C++ Michael T. Goodrich Roberto Tamassia David M. Mount Michael T. GoodrichRoberto TamassiaDavid M. Mount Chapter 2 Object-Oriented Design

2. Contents 2.1 Goals and Principles 2.2 Inheritance and Polymorphism 2.3 Templates 2.4 Exceptions 2.5 Recursion and Other Design Patterns 2.6 Exercises

3. 2.1 Goals and Principles Goals Robustness Adaptability Reusability Principles Abstraction Encapsulation Modularity

4. 2.2 Inheritance and Polymorphism 2.2.1 Inheritance in C++ class Person { private: string name; string ssn; public: //… void print(); string getName(); };

5. 2.2 Inheritance and Polymorphism class Student : public Person { private: string major; int gradYear; public: //… void print(); void changeMajor( string newMajor); };

6. 2.2 Inheritance and Polymorphism Member Functions void Person::print() { cout << “Name “ << name << ‘\n’; cout << “SSN “ << ssn << ‘\n’; } void Student::print() { Person::print(); cout << “Major “ << major << ‘\n’; cout << “Year “ << gradYear << ‘\n’; }

7. 2.2 Inheritance and Polymorphism Protected Members class { private: //… protected: //… public: //… };

8. 2.2 Inheritance and Polymorphism Constructors and Destructors Person::Person(const string &nm, const string &ss) : name(nm),// initialize name ssn(ss) { }// initialize ssn Student::Student(const string &nm, const string &ss, const string &maj, int year) : Person(nm, ss),// initialize Person members major(maj), // initialize member gradYear(year) { } // initialize graduation year Student* s = new Student(“John Smith”,”123-45-6789”,”Physics”,2010); Person::~Person()//Person destructor {…} Student::~Student()//Student destructor {…} delete s;//calls ~Student() then ~Person()

9. 2.2 Inheritance and Polymorphism Static Binding Person* pp[100]; pp[0] = new Person(…); pp[1] = new Student(…); cout getName() <<‘\n’;//okay pp[0] ->print(); pp[1] ->print(); pp[1] ->changeMajor(“English”);//ERROR!

10. 2.2 Inheritance and Polymorphism Dynamic Binding and Virtual Functions class Person { virtual void print() {….} //… }; class Student : public Person { virtual void print() {….} //… };

11. 2.2 Inheritance and Polymorphism 2.2.3 Examples of Inheritance in C++

12. 2.2 Inheritance and Polymorphism Arithmetic and Geometric Progression Classes

13. 2.2 Inheritance and Polymorphism A Fibonacci Progression Class

14. 2.2 Inheritance and Polymorphism

15. 2.2.4 Multiple Inheritance and Class Casting class Base { protected: int foo; public: int bar; }; class Derive1 : public Base { //foo is protected and bar is public }; class Derive2 : protected Base { //both foo and bar are protected }; class Derive3 : private Base { // both foo and bar are private };

16. 2.2 Inheritance and Polymorphism 2.2.5 Interfaces and Abstract Classes class Stack { public: bool isEmpty( ) const; void push(int x); int pop( ); };

17. 2.2 Inheritance and Polymorphism Interfaces and Abstract Base Classes class Stack { public: virtual bool isEmpty( ) const = 0; virtual void push(int x) = 0; virtual int pop( ) = 0; }; class ConcreteStack : public Stack { pribate: //…. public: virtual bool isEmpty( ) {…} virtual void push(int x) {…} virtual int pop( ) {…} };

18. 2.3 Templates 2.3.1 Function Templates int min(int a, int b) { return (a < b ? a : b); } template T min( T a, T b) { return (a < b ? a : b); }

19. 2.3 Templates 2.3.2 Class Templates template class BasicVector { Object* a; int capacity; public: BasicVector(int capac = 10) { capacity = capac; a = new Object[ capacity ]; } Object& elemAtRank(int r) { return a[r]; } //… };

20. 2.3 Templates 2.3.2 Class Templates BasicVector iv(5); BasicVector dv(20); BasicVector sv(10); //… iv. elemAtRank(3)= 8; dv. elemAtRank(14)= 2.5; sv. elemAtRank(7)= “hello”;

21. 2.3 Templates Templated Arguments BasicVector > xv(5); //… xv. elemAtRank(2). elemAtRank(8) = 15; Templated Members template Object& BasicVector ::elemAtRank(int r) { return a[r]; }

22. 2.4 Exceptions 2.4.1 Exceptions Object class MathException { private: string errMsg; public: MathException(const string& err) { errMsg = err; } };

23. 2.4 Exceptions Using Inheritance to Define New Exception Types class ZeroDivideException : public MathException { public: ZeroDivideException(const string& err) : MathException(err) { } }; class NegativeRootException : public MathException { public: NegativeRootException(const string& err) : MathException(err) { } };

24. 2.4 Exceptions 2.4.2 Throwing and Catching Exceptions try { if (divisor == 0 ) throw ZeroDivideException(“Divide by zero in Module X”); } catch (ZeroDivideException& zde) { //… } catch (MathException& me) { //… }

25. 2.4 Exceptions 2.4.3 Exceptions Specification void calculator( ) throw(ZeroDivideException, NegativeRootException ) { //function body… }

26. 2.4 Exceptions Generic Exception Class class RuntimeException { private: string errorMsg; public: RuntimeException( const string& err) {errorMsg = err; } string getMessage() const { return errorMsh; } }; inline std::ostream& operator <<(std::ostream& out, const RuntimeException& e) { return out << e.getMessage(); }

27. 2.5 Recursion and Other Design Patterns int recursiveFactorial(int n) { if (n==0) return 1; else return n*recursiveFactorial(n-1); }

28. 2.6 Exercises R-2.11 R-2.12