Question

1.

Write a class Rectangles which manages an array of Rectangle objects.

The constructor of the Rectangles takes an array of Rectangle objects. You can assume the array is filled

Provide these methods

• An averageArea method that returns the average area of the Rectangle objects in the array. Only divide one time
• A method swapMaxAndMin which swaps the Rectangle with the largest area with the one with the smallest area in the array. Only use one loop
• A method toString which returns the string representation of the underlying array. (You can use Arrays.toString)

Provide javadoc

Tester File:

RectanglesTester.java

import java.awt.Rectangle;

public class RectanglesTester
{


        public static void main(String[] args)
        {
                Rectangle[] recs = {
                                new Rectangle(30, 50,  5, 20),
                                new Rectangle(20, 40, 50, 40),
                                new Rectangle(10, 10, 20, 10),
                                new Rectangle(50, 10, 2, 8)
                };

                Rectangles processor = new Rectangles(recs);


                System.out.printf("Aveage: %.2f\n", processor.averageArea());
                System.out.println("Expected: 579.00");

                processor.swapMaxAndMin();
                System.out.println(processor.toString());
                System.out.println("Expected: [java.awt.Rectangle[x=30,y=50,width=5,height=20], java.awt.Rectangle[x=50,y=10,width=2,height=8], java.awt.Rectangle[x=10,y=10,width=20,height=10], java.awt.Rectangle[x=20,y=40,width=50,height=40]]");

                Rectangle[] recs2 = {
                                new Rectangle(30, 50,  5, 20),
                                new Rectangle(20, 40, 50, 40),
                                new Rectangle(10, 10, 20, 10),
                };

                Rectangles processor2 = new Rectangles(recs2);


                System.out.printf("Aveage: %.2f\n", processor2.averageArea());
                System.out.println("Expected: 766.67");

                processor2.swapMaxAndMin();
                System.out.println(processor2.toString());
                System.out.println("Expected: [java.awt.Rectangle[x=20,y=40,width=50,height=40], java.awt.Rectangle[x=30,y=50,width=5,height=20], java.awt.Rectangle[x=10,y=10,width=20,height=10]]");
        }
}

Answer 1

If you have any doubts, please give me comment...

import java.awt.Rectangle;

public class Rectangles{

    Rectangle rects[];

    public Rectangles(Rectangle inRects[]){

        rects = inRects;

    }

    private double area(Rectangle r){

        return r.getHeight()*r.getWidth();

    }

    public double averageArea(){

        double avg_area = 0.0;

        int len = rects.length;

        for(int i=0; i<len; i++){

            avg_area += area(rects[i]);

        }

        avg_area /= len;

        return avg_area;

    }

    public void swapMaxAndMin(){

        int max = 0;

        int min = 0;

        for(int i=1; i<rects.length; i++){

            if(area(rects[max])<area(rects[i]))

                max = i;

            if(area(rects[min])>area(rects[i]))

                min = i;

        }

        Rectangle temp = rects[max];

        rects[max] = rects[min];

        rects[min] = temp;

    }

    public String toString(){

        String result = "[";

        for(int i=0; i<rects.length; i++){

            result += rects[i];

            if(i!=rects.length-1)

                result+=", ";

        }

        result += "]";

        return result;

    }

}