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Zeeshan Hanif

Software Development Training Program

Zeeshan Hanif

Zeeshan Hanif

DotNet 3.5-101 Lecture 7

Zeeshan Hanifzee81zee@yahoo.com

zeeshan_java@hotmail.com

Zeeshan Hanif

Inheritance What is Inheritance Inherited Members new method virtual and override methods Polymorphism Abstract classes Sealed classes Object class Boxing and Unboxing Interfaces

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Inheritance

Inheritance is a powerful mechanism that allows a class to inherit functionality from an existing class.

For example, Cat, Dog, both are kinds of Mammal.

Car and Bus both are kinds of Vehicle

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is-a Relationship

The is-a relationship is one of specialization.

When we say, Dog is-a mammal, means dog is specialized kind of mammal

Mammal is generalization kind of Dog

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Car

Luxury cars

Sports Car

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Inheritance

In object-oriented terminology, sports cars and luxury cars are derivedclasses of car class. Similarly, the car class is the baseclass of luxury car and sports car.

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Example

public class Car {public int wheels;public string color;

}public class SportsCar : Car {

public int noOfSeats;}

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Inheritance Each derived class inherits all

variables from the base class. Sports cars and luxury cars both inherits four wheels, gears etc.

Also, each derived class inherits methods from the base class. Luxury cars and sports cars share some behaviors: braking and changing speed, for example.

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Inheritance

A However, derived classes are not limited to the state and behaviors provided to them by their base class.

Derived classes can add more variables and methods. Sports cars have two seats and, some sports cars have an extra set of gears.

Zeeshan Hanif

Inheritance What is Inheritance Inherited Members new method virtual and override methods Polymorphism Abstract classes Sealed classes Object class Boxing and Unboxing Interfaces