Area of A Rectangle Using Two Co-Ordinates. [Class-Objects]

#include <iostream>

using namespace std;

class Point{

private:
    int x, y;

public:
    void readData ()
    {
        cin >> x;
        cin >> y;
    }

    int getx () { return x;}
    int gety () { return y;}
};

class Rectangle{

private:
    class Point tr, bl;

public:
    void setPoint ()
    {
        cout << "Top-Right Point: ";
        tr.readData();
        cout << "Bottom-Left Point: ";
        bl.readData();
    }

    int getx1() { return tr.getx();}
    int getx2() { return bl.getx();}
    int gety1() { return tr.gety();}
    int gety2() { return bl.gety();}
};

void area (Rectangle X);

main()
{
    class Rectangle R;

    cout << "This Program Can Calculate the Area of A Rectangle Using 2 (Cartesian) Co-Ordinates" << endl;

    cout << "Enter Points" << endl;
    R.setPoint();

    area (R);

    return 0;
}

void area (Rectangle X)
{
    int A, x1, x2, y1, y2;

    x1 = X.getx1();
    x2 = X.getx2();
    y1 = X.gety1();
    y2 = X.gety2();

    A = (x1 - x2) * (y1 - y2);

    cout << "Area is: " << A;
    return;
}