Question

1A - First class is named Rectangle. The class will utilize two fields to define the object. One to represent length and use another field to define the width. Create a constructor to set the length and width to user-specified values. These user values will be asked for and received using a MESSAGE BOX. Write get and set methods for all variables. You need to create a method (name it whatever you want) that will calculate the AREA of the rectangle. Be sure it is a NON-VOID method that returns the area of a rectangle. Do the same by creating a second method that returns the perimeter of a rectangle. You can name all methods, fields (variables) anything you like. Call your class Rectangle.java. 1B - Write a second class TestRectangle.java that creates two rectangles, one with values 3 and 4, and one with values 7 and 5. The program then displays the length, width area and perimeter of each rectangle by calling the methods you created within Rectangle. Do not do any calculations in this TestRectangle; only call methods to perform the calculations. Do not put your code in the editor below. SUBMIT YOUR JAVA OR TXT FILE in the Additional Content section BELOW.

Answer 1

1A - Rectangle.java

```java

import javax.swing.JOptionPane;

public class Rectangle {

private double length;

private double width;

public Rectangle() {

setLength(Double.parseDouble(JOptionPane.showInputDialog("Enter length:")));

setWidth(Double.parseDouble(JOptionPane.showInputDialog("Enter width:")));

}

public double getLength() {

return length;

}

public void setLength(double length) {

this.length = length;

}

public double getWidth() {

return width;

}

public void setWidth(double width) {

this.width = width;

}

public double calculateArea() {

return getLength() * getWidth();

}

public double calculatePerimeter() {

return 2 * (getLength() + getWidth());

}

}

```

1B - TestRectangle.java

```java

public class TestRectangle {

public static void main(String[] args) {

Rectangle rectangle1 = new Rectangle();

Rectangle rectangle2 = new Rectangle();

System.out.println("Rectangle 1: Length = " + rectangle1.getLength() + ", Width = " + rectangle1.getWidth());

System.out.println("Area: " + rectangle1.calculateArea());

System.out.println("Perimeter: " + rectangle1.calculatePerimeter());

System.out.println("\\Rectangle 2: Length = " + rectangle2.getLength() + ", Width = " + rectangle2.getWidth());

System.out.println("Area: " + rectangle2.calculateArea());

System.out.println("Perimeter: " + rectangle2.calculatePerimeter());

}

}

```

Step-by-step explanation

In the provided Java code, we have two classes: `Rectangle` and `TestRectangle`. In the `Rectangle` class (1A), a constructor is created to initialize the length and width of a rectangle with user-specified values obtained through a message box. Getter and setter methods are also defined for both length and width. Additionally, two methods, `calculateArea()` and `calculatePerimeter()`, are included to compute the area and perimeter of the rectangle, respectively.

In the `TestRectangle` class (1B), two instances of the `Rectangle` class are created, representing two rectangles with different length and width values. The program then prints the length, width, area, and perimeter of each rectangle by calling the methods defined in the `Rectangle` class. The main purpose of this class is to test the functionality of the `Rectangle` class without performing any calculations within the `TestRectangle` class itself.

By following this structure, the code adheres to object-oriented principles, encapsulating the properties and behaviors of a rectangle within the `Rectangle` class and demonstrating their use in the `TestRectangle` class.