Program to demonstrate Using Object as Parameters

/* Program to demonstrate ‘Using Object as Parameters’ */

class Rectangle
{
    int length;
    int width;

    // Construct clone of an object
    Rectangle(Rectangle obj)
    {       
        length = obj.length;
        width = obj.width;
    }

    //  Constructor used when all values are specified
    Rectangle(int l,int w)
    {       
        length = l;
        width = w;
    }

    //  Constructor used when no values are specified
    Rectangle()
    {   
        length = 0;       
        width = 0;
    }

    //  Constructor used when one value is specified for both,length and width
    Rectangle(int l)
    {       
        length = width = l;
       
    }

    // compute and return Area of a Rectangle
    int area()
    {
        return length*width;
    }
   
}


class RectangleDemo9
{
    public static void main(String args[])
    {
        // create Rectangles using the various constructors
        Rectangle rect1 = new Rectangle(20,15);
        Rectangle rect2 = new Rectangle();
        Rectangle rect3 = new Rectangle(20);
        int a;

        Rectangle rect4 = new Rectangle(rect1);
   
       
        // get area of first rectangle
        a = rect1.area();         
        System.out.println("Area of First Rectangle(length:"+rect1.length+", width:"+rect1.width+") is: "+a);
       
        // get area of second rectangle
        a= rect2.area();         
        System.out.println("Area of Second Rectangle(length:"+rect2.length+", width:"+rect2.width+") is: "+a);

        // get area of Third rectangle
        a= rect3.area();         
        System.out.println("Area of Third Rectangle(length:"+rect3.length+", width:"+rect3.width+") is: "+a);

        // get area of clone
        a= rect4.area();         
        System.out.println("Area of Clone(length:"+rect4.length+", width:"+rect4.width+") is: "+a);
    }
}