Abstract class in c++

Abstract class in c++

• 1.
  ABSTRACT CLASS Name: Md.Sujan Mia Session: 2016-17 Id: 154085
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  OVERVIEW OF ABSTRACTCLASS?  What is abstract class?  How to make abstract class ?  How to use abstract class ?  Importance of abstract class ?
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  WHAT IS ABSTRACTCLASS? Abstract class :  An abstract class is a class that is designed to be specific used as a base class .  we can’t create objects of abstract classes.  An abstract class contains at least one pure base class.
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  HOW TO MAKEABSTRACT CLASS?  An abstract class contains at least one pure virtual function. Declare a pure virtual function by using a pure specifier (= 0) in the declaration of a virtual member function. The following is an example of an abstract class: class abstract { public: virtual void f() = 0; //pure virtual function that };
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  HOW TO USEABSTRACT CLASS ? //this is simple program of abstract class. #include <iostream> using namespace std; class Abstract { int x, y; public: virtual void setData(int x = 0, int y = 0) = 0; //pure virtual member virtual void printData() = 0; }; class Derived : public Abstract { int x, y; public: void setData(int a= 0, int b= 0) { x = a; y = b; }
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  void printData() { cout <<"Derived::x = " << x << endl << "Derived::y = " << y << endl; } }; int main() { Derived d; //new data set. d.setData(10, 20); cout << “Set New data " << endl; d.printData(); } OUTPUT: Set New data: Derived::x =10 Derived::y=20
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  IMPORTANCE OF ABSTRACTCLASS?  An abstract class as a base class is needed when there is functionality that is desired for all objects that have a type deriving from Abstract Class, but we cannot be implemented on the Abstract Class itself.
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  THANK YOU