Question

What if you had to write a program that would keep track of a list of rectangles? This might be for a house painter to use in calculating square footage of walls that need paint, or for an advertising agency to keep track of the space available on billboards.

The first step would be to define a class where one object represents one rectangle's length and width. Once we have class Rectangle, then we can make as many objects of class Rectangle as we want and store all of them in an ArrayList. Class ArrayList is defined in the Java API. https://docs.oracle.com/javase/8/docs/api/index.html

Attached you will find a file called "Rectangle.java".Rectangle.java Inside this source code file is the definition of class Rectangle. One object of class Rectangle represents the length and width of a rectangle.

Step 1) In order to familiarize yourself with this class Rectangle (attached), create a second source code file that defines a second class TestRectangle. This class TestRectangle contains "public static void main(String[] args)". Inside this main(), write the Java code that creates a few new Rectangle objects of different sizes, and calls the methods from class Rectangle on those objects. You do not need to submit this code, it is just so that you understand how to create new Rectangle objects and call methods on these new objects.

Once you are able to create new Rectangle objects and call methods on these new objects, then are ready to write the main() that will satisfy the requirements of this assignment.

Step 2) In the main() of class TestRectangle, prompt the user and read the length and width for one Rectangle object. Construct a new Rectangle object and set the length and width to the user's input values.

Step 3) In the main() of class TestRectangle, define a new ArrayList of Rectangle objects. Add the Rectangle object you constructed in Step 2) to the ArrayList. Print the ArrayList to confirm that your Rectangle object got into the ArrayList.

Step 4) Write a loop that repeats this process four times. Your main() will now prompt and read the length and width from the user, create a new Rectangle object and add it to the ArrayList - four times. At this point you must have a total of 4 Rectangle objects inside your one ArrayList. Print the ArrayList so that you can verify that all 4 Rectangle objects are in the ArrayList.

Hints:

-Start Step 4) by writing down what will appear on the console when your program is completed. You will not be able to write a program if you don't know exactly how this program should work.

-If both of these source code files are in the same project, you will not need to import Rectangle in the source code file that contains the main().

-Declare a final int for the number of Rectangle objects read from the user, so that it is easy to change the number of Rectangle objects that are stored by your program.

Rectangle.java

/**

* One object of this class represents a rectangle's length and width.

*/

public class Rectangle {

private int length;

private int width;

/**

* returns the length of the Rectangle object

*/

public int getLength() {

return this.length;

}

/**

* sets the length of the Rectangle to "newLength"

*/

public void setLength(int newLength) {

this.length = newLength;

}

/**

* returns the width fo the Rectangle object

*/

public int getWidth() {

return this.width;

}

/**

* Sets the width of the Rectangle to "newWidth"

*/

public void setWidth(int newWidth) {

this.width = newWidth;

}

/**

* Returns a String containing the length and

* width of the Rectangle.

*/

public String toString() {

return "For this Rectangle: length = " + this.length + ",

and width = " + this.width;

}

}

Answer 1

*****************************************Code********************************************

import java.util.*;

/*** One object of this class represents a rectangle's length and width.*/

class Rectangle {
    private int length;
    private int width;

    /*** returns the length of the Rectangle object*/
    public int getLength() {
        return this.length;// Returns the length
    }

    /*** sets the length of the Rectangle to "newLength"*/
    public void setLength(int newLength) {
        this.length = newLength;//Used to set length
    }

    /*** returns the width fo the Rectangle object*/
    public int getWidth() {
        return this.width;//Used to get width
    }

    /*** Sets the width of the Rectangle to "newWidth"*/
    public void setWidth(int newWidth) {
        this.width = newWidth;//Used to set width
    }

    /*** Returns a String containing the length and * width of the Rectangle.*/
    public String toString() {
        return "For this Rectangle: length = " + this.length + ",and width = " + this.width;

    }
}

public class example {
    // numberOfObjects is final variable which will store the how many objects do we have to create
    private static final int numberOfObjects = 4;

    public static void main(String args[]) {
        // Creating scanner object for taking the data from the user
        Scanner in = new Scanner(System.in);
        ArrayList<Rectangle> al = new ArrayList<>();
        // Creating the arrayList of type Rectangle for storing the rectangle objects
        for (int i = 0; i < numberOfObjects; i++) {
            // Iterating the numberOfObjects times for taking the data from the user
            Rectangle r = new Rectangle();
            System.out.print("Enter the length and width:");
            // Prompting the user for entering the length and width
            r.setLength(in.nextInt());
            r.setWidth(in.nextInt());
            // setting the user given data to rectangle objects using setters
            al.add(r);
            //adding the rectangle object to array list
            System.out.println("*************************");
            System.out.println("Array List Elements:");
            for (Rectangle r1 : al) {
                // Printing the array list elements using for each method
                System.out.println(r1.toString());
                System.out.println("--------------------------");
            }
            System.out.println("*************************");
        }
        System.out.println("All the array list elements");
        // Displaying the all the contents of the array list
        for (Rectangle r1 : al) {
            System.out.println(r1.toString());
            System.out.println("--------------------------");
        }
    }
}

*****************************************Code Screens********************************************

41 42 43 7Creating scanner object for taking the data from the user Scanner innew Scanner(System. in); ArrayList<Rectangle> alnew ArrayList<>(); Creating the arrayList of type Rectangle for storing the rectangle objects for (int i = 0; 1 numberOfObjects ; 1++) { 45 46 Iterating the numberOfobjects times for taking the data from the user Rectangle r = new Rectangle(); System.out.print ("Enter the length and width:"); 7Prompting the user for entering the length and width r.setLength(in.nextInt ()); r.setWidth(in.nextInt()); /setting the user given data to rectangle objects using setters al.add(r); //adding the rectangle object to array list 48 49 50 52 53 54 System.out.println ("Array List Elements:"); for (Rectangle rl : al) 56 57 58 59 60 Printing the array list elements using for each method System. out.println (r1.toString()); System.out.println("---"); 62 63 64 65 System.out.println ("All the array list elements"); Displaying the all the contents of the array list for (Rectangle rl : al) System. out.println (r1.toString()); System.out.println("---"); 67 68 69 70 71

*****************************************Output Screens********************************************

sys1091@sys1091:~/IdeaProjects/ds/src$ javac example.java sys1091@sys1091:~/IdeaProjects/ds/src$ java example Enter the length and width:1 2 RKKK Array List Elements: For this Rectangle: ength 1,and width-2 RKKK Enter the length and width:2 3 RKKK Array List Elements: For this Rectangle: ength 1,and width-2 For this Rectangle: ength 2,and width3 RKKK Enter the length and width:3 4 RKKK Array List Elements: For this Rectangle: ength 1,and width-2 For this Rectangle: ength 2,and width3 For this Rectangle: ength 3,and width 4 Enter the length and width:4 5 RKKK RKKK Array List Elements: For this Rectangle: ength 1,and width-2 For this Rectangle: ength 2,and width3 For this Rectangle: ength 3,and width 4 For this Rectangle: ength 4,and width 5 RKKK All the array list elements For this Rectangle: length 1,and width-2 For this Rectangle: ength 2,and width3 For this Rectangle: ength 3,and width 4 For this Rectangle: length = 4,and width = 5

sys1091@sys1091:/IdeaProjects/ds/srcs java example Enter the length and width:2 3 RKKKR Array List Elements: For this Rectangle: length 2,and width3 Enter the length and width:34 Array List Elements: RKKKR RKKKR For this Rectangle: length 2,and width3 For this Rectangle: length 3,and width 4 Enter the length and width:10 20 Array List Elements: RKKKR RKKKR For this Rectangle: length 2,and width3 For this Rectangle: length 3,and width 4 For this Rectangle: length 10, and width 2θ Enter the length and width:39 40 Array List Elements: RKKKR RKKKR For this Rectangle: length 2,and width3 For this Rectangle: length 3,and width 4 For this Rectangle: length 10,and width 2θ For this Rectangle : length 30, and width -4θ All the array ist elements RKKKR For this Rectangle: length 2,and width3 For this Rectangle: length 3,and width 4 For this Rectangle: length 10, and width 2θ For this Rectangle: length 30,and width -4θ sys1091@sys1091:-/IdeaProjects/ds/src$

sys1091@sys1091:~/IdeaProjects/ds/src$ java example Enter the length and width:100 200 Array List Elements: For this Rectangle: length 100,and width 200 Enter the length and width: 2θθ 300 Array List Elements: RKKKR For this Rectangle: length 100, and width 2θθ For this Rectangle: length 2θθ , and width 3θθ RKKKR Enter the length and width:10 2θ RKKKR Array List Elements: For this Rectangle: length 100, and width 2θθ For this Rectangle: length 2θθ , and width 3θθ For this Rectangle: length 10,and width 2θ Enter the length and width:1 2 Array List Elements: RKKKR RKKKR For this Rectangle: length 100,and width 200 For this Rectangle: length 2θθ , and width 3θθ For this Rectangle: length 10,and width-20 For this Rectangle: length 1,and width 2 RKKKR All the array list elements For this Rectangle: length 100,and width 2θθ For this Rectangle: length 2θθ , and width 3θθ For this Rectangle: length 10,and width 2θ For this Rectangle: length 1,and width 2 sys1091@sys1091:-/IdeaProjects/ds/src$