Write a C++ program to illustrate pur virtual function and calculate the area of different shapes by using abstract class.

AIM: Write a C++ program to illustrate pur virtual function and calculate the area of different shapes by using abstract class.

THEORY:

In C++, if a class has at least one pure virtual function, then the class becomes abstract. Unlike C++, in Java, a separate keyword abstract is used to make a class abstract.

// An example abstract class in Java abstract class Shape {     int color;     // An abstract function (like a pure virtual function in C++)     abstract void draw(); }

SOURCE CODE:

#include"as.h"

#include<iostream>

class square:public A

{

            public:

            int w;

            square(int x)

            {

                        w=2;

                        }         

                        int area()

                        {

                                    return w*w;

                        }

};

class rectangle:public A

{

            public:

            int l,w;

            rectangle(int x,int y)   

            {

                        l=y;

                        w=x;

            }

            int area()

            {

                        return w*l;

            }

};

class cube:public A

{

            public:

            int w;

            cube(int x)      

            {

                        w=x;

            }

            int area()

            {

                        return 6*w*w;

            }

};

class AB:public A

{

           

};

int main()

{

            square *p,s(5);

            p=&s;

            cout<<"\n Area of square:"<<p->area();

            rectangle r(10,3);

            cout<<"\n Area of reactangle:"<<r.area();

            cube c(3);

            cout<<"\n Area of cube:"<<c.area();

            AB a;

            cout<<a.area();

}