Data Structures and Algorithms in C++ Michael T. Goodrich Roberto Tamassia David M. Mount

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

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

2.1 Goals and Principles • Goals Robustness Adaptability Reusability • Principles Abstraction Encapsulation Modularity

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

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

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’; }

2.2 Inheritance and Polymorphism Protected Members class <class_name> { private: //… protected: //… public: //… };

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()

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

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

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

2.2 Inheritance and Polymorphism Arithmetic and Geometric Progression Classes

2.2 Inheritance and Polymorphism A Fibonacci Progression Class

2.2 Inheritance and Polymorphism

2.2 Inheritance and Polymorphism 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 };

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

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

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

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

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

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

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

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) { } };

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) { //… }

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

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

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

2.6 Exercises • R-2.11 • R-2.12

Data Structures and Algorithms in C++ Michael T. Goodrich Roberto Tamassia David M. Mount