Object Oriented Programming

Object Oriented Programming. LECTURE 7 Math.262. Dr. Nermeen Elhamy.

The Default Copy Constructor - Itis another way to initialize an object: - Used to initialize an object with another object of the same type. - No need to create a special constructor for this; one is already built into Class : Distance Feet Inches Distance ( ) —Distance ( ) Object 1 Feet = 5 Inches = 3.5 Object 2 Feet -5 Inches = 3.5.

The Default Copy Constructor class Distance //EngIish Distance class private: int feet; float inches; public: Distance() : feet(O), inches(O.O) Distance(int ft, float in) : feet(ft), inches(in) int main() Distance d 1; Distance dist2 (II, 6.25); Distance dist3 (dist2); Distance dist4 = dist2;.

private : int feet; float inches; public: Distance ( ) ; Distance (int f, float i) ; void setDistance (int f, float i) ; void print ( ) ; &Distance ( ) ;.

void Distance: : setDistance (int f; inches = 1 €void Distance: :print ( ) f, float cout << "Feet = feet i) " inches inch.

3 4 5 6 7 8 9 10 11 12 13 14 15 16 E#include "pch.h" #include <iostream> #include "Distance.h" Sint main() Distance dl; Distance d2(5, 3.5) Distance d3 (d2) ; d3 .print ; d3 . setDistance (7 , 4.25); Distance d4 = d3; d4 .print ( ) ; Microsoft Visual Studio Console Feet = S eet = 7 inches = 3.5 inches = 4.25 : SOneDriue — •class .exe (process 848D exited with code ress any key to close this window ..

Exercise. Write a class for a book class that contains the following members : 1- The name of the book 2- his number 3- Its price 4- the author’s name 5- The number of the book 6- count And contains the following functions: 1- A default constructor and a mediator's constructor. 2-Properties of get && set 3- A function to search for a book by its name. 4- A function for selling a book by the book number, and this function returns the amount of the remaining books.

Static Class Members • Static fields and static methods do not belong to a Single instance ofa class. • A static data item is useful when all objects of the same class must share a common information. • Its lifetime is the entire program. It continues to exist even if there are no objects of the class. • To invoke a static method or a static field, use the class name the instance name..

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Ex. Class Car {. private: string maker; int model; string color; int count =OI; public: void setMaker (string m) ; string getMaker ( ) ; void setMode1 (int m) ; int getMode1 ( ) ; int Getcarscount ( ) ; Car (string m, int mo, string c) ;.

:Car (string m, •Car : count++ ; scar: FCar count-- ; int mo, string c) :maker (m) ,model (mo).

E#include "pch.h" #include <iostream> I *include "Car . h" Sint main() Car cl; cout<<"Counter reached "<< cl .GetCarscount ( ) ; Car c2; cout << "Counter reached " << c2.GetCarscount ( ).

using namespace std; —class Car private : string maker; int model; string color; static int countl public : void setMaker (string m) ; string getMaker () ; void setMode1 (int int getMode1 ( ) ;.

Firstc++class 1 2 3 4 5 6 7 8 9 10 (Global Scope) s#include "pch.h" *include "Car. h" #include<iostream> using namespace std; int car: :count = scar: :car ( ) :maker ("Toyota") , model (2019) , color ("White") count++;.

Then , Run the program. Distance.h Firste + class 4 5 6 7 8 9 Distance.cpp pch.cpp Firstc++class.cpp (Global Scope) include "pch.h" #include <iostream> #include "Car . h" Sint main() Car cl; cout<<"Counter reached 10 11 12 13 14 15 1 1 1 Car c2; cout << car c3; "Counter reached " cl . Getcar c2.GetC ' Microsoft Visual Studio Debug Console Counter reached 1 Counter reached 2 tountep reached 3.

Static Methods • Static methods are convenient because they may be called at the class level. They are typically used to create utility classes. • Static methods may not communicate with Instance fields, only static fields..

Ex. I Sot•.nion Explorer Search Solution Explorer (Ctrl•; p • Solution (l References G External Dependencies Header Files Calculator.h Car.h Distance.h Rectangle.h Resource Files Source files +4 Calculator.cpp +4 Qr.cpp Calculator.cpp• Firstc• • class 2 3 4 5 6 8 9 10 11 12 13 *include Distance.cpp c <string> pchcpp pch.h • Calculator hrstc• • class.( using namespace std; -class calculator public: static int add(int numl, int num2) ; static int mutiply (int numl, int num2) ; static lint subtract (int numl, int num2) ; Calculator () ; &CaIcuIator () ;.

How Calling utility class (static method). 4 5 6 7 8 9 10 11 12 13 14 8 #include "pch. h" # include <iostream> #include "Calculator . h" [Sint main ( ) Calculator: • .add(2, 5); :mutip1y(3, 5) ; Calculator: Calculator: : subtract (10, 2) ;.

Inheritance. What is Inheritance? • Inheritance is probably the most powerful feature of object-oriented programming, after classes themselves. Inheritance is the process of creating new classes, called derived classes, from existing or classes • The derived class inherits all the capabilities of the base class but can add its own features. And the base class is unchanged by this process..

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"'ith Inheritance Person —Last name —First name —Address —Home phone +Ugxiate address() Employee —Hire date —pay grade +Ugxiate pay grade() Customer —Last contact date last contact date().

Class • > - Age - Nationality Get _ Age ( ) Get _ a&fress ( ) •Set _ Nationality •Get_ Nationality ) Sub Studen t - Study _ Level • ialization GPA • Get _ ) • Set _ Specialization ( ) • Get _ Specialization ( ) • Set_GPA ( e <Sub Class* • - Salary • Rank • Set _ Salary ( ) Get _ Salary ) Set_rank ( ) Get _ rank ) Set _ Job ( ) Get_Job ) < «Sub Class* Salaried Employee - Deductions • Set _ Working_hours ( ) + Get _ Working_hours ( ) Get _ Houre_Rate ( ) Sub Class* Hourly Employee - Working _ Hours - _ rate • Set _ Working. hours ( ) • Get _Working _ hours ( ).

Each derived class, in turn, can become a base class for a future derived class. Inheri- tance can be either single inheritance or multiple inheritance. In single inheritance, the derived class is derived from a single base class; in multiple inheritance, the derived class is derived from more than one base class. This chapter concentrates on single inheritance..

The protected Members. A protected member variable or function is very similar to a private member but it provided one additional benefit that they can be accessed in child classes which are called derived classes..

To define a derived class ,. class derived-class : access- specifier base-class Class derived-class : < inheritance type > base-class.

Type of Inheritance. When deriving a class from a base class, the base class may be inherited through public, protected or private inheritance. The type of inheritance is specified by the access-specifier as explained above. We hardly use protected or private inheritance, but public inheritance is commonly used. While using different type of inheritance, following rules are applied : • Public Inheritance: When deriving a class from a public base class, public members of the base class become public members of the derived class and protected members of the base class become protected members of the derived class. A base class's private members are never accessible directly from a derived class, but be accessed through calls to can the public and protected members of the base class..

Type of Inheritance. • deriving from a protected base Protected Inheritance: When class, public and protected members of the base class become protected members of the derived class..

Access Control and Inheritance. A derived class can access all the non-private members of its base class . Thus base-class members that should not be accessible to the member functions of derived classes should be declared private in the base class . We can summarize the different access types according to - who can access them , in the following way:.

Example. Consider a base class Shape and its derived class Rectangle as follows: class Shape void setHeight ( int h) } height = h; ;.

int main(void) } Rectangle Rect ; Rect.setWidth (5); Rect.setHeight (7); // Print the area of the object. cout << "Total area: " << Rect.getArea () << endl ; return 0; {.

Multiple Inheritance. A C++ class can inherit members from more than one class and here is the extended syntax : class derived-class : access baseA , access baseB , .... Where access is one of public, protected, or private and would be given for every base class and they will be separated by comma as shown above..

*include using namespace std; / / Base class Shape class Shape public : void setWidth( w) width void setHeight ( int height = h; protected : int width; int height;.

int main(void) Rectangle Rect; int area; Rect . setWidth(5); Rect . setHeight(7); area = Rect . getArea( ) ; // Print the area of the object. Rect . getArea() << endl; cout << "Total area: ' // Print the total cost of painting cout << "Total paint cost: $" << Rect. getCost(area) << endl; return 0;.

A derived class inherits all base class methods with the following exceptions: • Constructors, destructors and copy constructors of the base class. • Overloaded operators of the base class. • The friend functions of the base class,.