Typecast in C++ through an example (Class to Class)

#include<iostream.h>

#include<conio.h>

#include<math.h>

const double pi=3.141592654;

class rectangular

{

            double x,y;

            public:

                        rectangular():x(0),y(0){}

                        rectangular(double a,double b)

                        {

                                    x=a;

                                    y=b;

                        }

                        double getx()

                        {

                                    return x;

      }

                        double gety()

                        {

                                    return y;

                        }

                        void input()

                        {

                                    cout<<" \nENTER THE COORDINATES"<<endl;

                                    cin>>x>>y;

                        }

                        void output()

                        {

                                    cout<<"("<<x<<","<<y<<")";

                        }

};

class polar

{

            double theta,r;

            public:

                        polar():theta(0),r(0){}

                        polar(rectangular rect)

                        {

                                    r=sqrt(rect.getx()*rect.getx()+rect.gety()+rect.gety());

                                    theta=atan(rect.gety()/rect.getx());

                                    theta=(theta*180)/pi;

                        }

                        operator rectangular()

                        {

            double x,y;

                                    float atheta=theta*pi/180;

                                    x=r*cos(atheta);

                                    y=r*sin(atheta);

                                    return rectangular(x,y);

                        }

                        void input()

                        {

                                    cout<<"\nENTER THE POLAR COORDINATE: ";

                                    cin>>r>>theta;

                        }

                        void output()

                        {

                                    cout<<"\nr="<<r;

                                    cout<<"\ntheta="<<theta;

      }

};

void main()

{

            rectangular r1,r2;

            polar p1,p2;

            int ch,n;

            do

            {

                        cout<<"\n\t\t-----------";

                        cout<<"\n\t\t CONVERSION";

                        cout<<"\n\t\t-----------";

                        cout<<"\n1.RECTANGULAR TO POLAR \n2.POLAR TO RECTANGULAR:"<<endl;

                        cin>>ch;

                        switch(ch)

                        {

                        case 1:

                                    r1.input();

                                    p1=r1;

                                    cout<<"\nPolar coordintes of polar:";

                                    p1.output();

                                    break;

                        case 2:

                                    p2.input();

                                    r2=p2;

                                    cout<<"\nRectangular coordinates are:";

                                    r2.output();

                                    break;

                        }

                        cout<<"\nDO U WANT TO CONTINUE:1:yes 2:No";

                        cin>>n;

            }while(n==1);

   getch();

}