Question:

Consider the following class definition:

public class Rectangle {
    
    private double length;
    private double width;
    
    // Constructor
    
    // Getter and Setter methods
        
    // Method to calculate the area of rectangle
    
    // Method to calculate the perimeter of rectangle
    
    // Method to check if the rectangle is a square
    
    // Main method for testing
    
}

a) Complete the class definition above by implementing the following:

• A constructor that takes in two parameters length and width and initializes the respective instance variables.

• Getter and Setter methods for the instance variables length and width.

• A method named calculateArea that calculates and returns the area of the rectangle using the formula area = length * width.

• A method named calculatePerimeter that calculates and returns the perimeter of the rectangle using the formula perimeter = 2 * (length + width).

• A method named isSquare that checks if the rectangle is a square. A rectangle is considered a square if its length and width are equal. The method should return true if the rectangle is a square, and false otherwise.

b) Write the code for the Rectangle class's constructor, getter and setter methods, calculateArea method, calculatePerimeter method, and isSquare method.

c) Write a complete main method to test the Rectangle class. Create two objects of Rectangle class, one with length 4 and width 5, and the other with length 6 and width 6. Print the area and perimeter of both rectangles, and check if they are squares.

Answer:

The modified class definition is as follows:

public class Rectangle {
    
    private double length;
    private double width;
    
    // Constructor
    public Rectangle(double length, double width) {
        this.length = length;
        this.width = width;
    }
    
    // Getter and Setter methods
    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;
    }
        
    // Method to calculate the area of rectangle
    public double calculateArea() {
        return length * width;
    }
    
    // Method to calculate the perimeter of rectangle
    public double calculatePerimeter() {
        return 2 * (length + width);
    }
    
    // Method to check if the rectangle is a square
    public boolean isSquare() {
        return length == width;
    }
    
    // Main method for testing
    public static void main(String[] args) {
        // Create two objects of Rectangle class
        Rectangle rectangle1 = new Rectangle(4, 5);
        Rectangle rectangle2 = new Rectangle(6, 6);
        
        // Print the area and perimeter of both rectangles
        System.out.println("Rectangle 1:");
        System.out.println("Area: " + rectangle1.calculateArea());
        System.out.println("Perimeter: " + rectangle1.calculatePerimeter());
        
        System.out.println("\nRectangle 2:");
        System.out.println("Area: " + rectangle2.calculateArea());
        System.out.println("Perimeter: " + rectangle2.calculatePerimeter());
        
        // Check if the rectangles are squares
        System.out.println("\nRectangle 1 is a square: " + rectangle1.isSquare());
        System.out.println("Rectangle 2 is a square: " + rectangle2.isSquare());
    }
}

Explanation:

a) The class definition has been modified to include the necessary elements:

• A constructor is added which receives length and width as parameters and initializes the respective instance variables length and width.

• Getter and Setter methods are added to access and modify the values of length and width.

• The calculateArea method calculates the area of the rectangle by multiplying the length and width and returns the calculated value.

• The calculatePerimeter method calculates the perimeter of the rectangle using the formula 2 * (length + width) and returns the calculated value.

• The isSquare method checks if the rectangle is a square by comparing the length and width. If they are equal, it returns true, otherwise, it returns false.

b) The code for the Rectangle class's constructor, getter and setter methods, calculateArea method, calculatePerimeter method, and isSquare method is written as shown above.

c) The main method is implemented to test the Rectangle class. Two objects of the Rectangle class are created, one with a length of 4 and width of 5, and the other with a length of 6 and width of 6. The area and perimeter of both rectangles are printed, and then it is checked if they are squares by calling the isSquare method. The results are printed accordingly.