Question

Java Code - Please explain each step through comments. Also, make sure Main (P3_13) is separate from your class BetterRectangle. Lastly, post a picture of your code inside an IDE along with your output. My code is below, needs modification.

E9.13The java.awt.Rectangle class of the standard Java library does not supply a method to compute the area or perimeter of a rectangle. Provide a subclass BetterRectangle ofthe Rectangle class that has getPerimeter and getArea methods. Do not add any instance variables. In the constructor, call the setLocation and setSizemethods of the Rectangleclass. In E9_13 class, provide 3test cases that tests the methods that you supplied printing expected and actual results. The test cases are: 1) One positive test case testing your method with valid inputs 2) Two negative test cases, testing your methods for invalid inputs, and printing proper error message indicating proper error handling.

Please Fix my code with comments and with instructions.

/BetterRectangle.java

import java.awt.Rectangle;

public class BetterRectangle extends Rectangle{

      

// default constructor

       public BetterRectangle()

       {

             super();

       }

      

       public BetterRectangle(int x, int y, int width, int height)

       {

             super();

             setSize(width,height);

             setLocation(x,y);

       }

      

       public double getArea()

       {

             return(getWidth()*getHeight());

       }

      

       public double getPerimeter()

       {

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

       }

      

       public static void main(String[] args) {

              // test the class

             BetterRectangle rect1 = new BetterRectangle(0,0,20,30);

             System.out.println("Area : "+rect1.getArea());

             System.out.println("Perimeter : "+rect1.getPerimeter());

       }

}

//end of BetterRectangle.java

Answer 1

// BetterRectangle.java

import java.awt.Rectangle;

public class BetterRectangle extends Rectangle{

   // default constructor that sets the left-top coordinate to (0,0) and height and width to 1
   public BetterRectangle()
   {
       super(); // call default constructor of Rectangle class
       setSize(1,1); // set width and height of rectangle to 1
}
  
   // parameterized constructor that sets the left-top coordinate to (x,y) and width and height to passed values
   public BetterRectangle(int x, int y, int width, int height)
   {
       super(); // call default constructor of Rectangle class
      
       // validate both width and height of the Rectangle > 0, if not throw exception
       if(width <= 0 || height <= 0)
           throw new IllegalArgumentException("ERROR: Width or/and height of the rectangle must be greater than 0.");
       setSize(width,height); // set width and height of rectangle to width and height respectively
       setLocation(x,y); // set left-top coordinate to (x, y)
}
  
   // method that calculates the area of the rectangle and return it
   public double getArea()
   {
       return(getWidth()*getHeight());
}

   // method that calculates the perimeter of the rectangle and return it
   public double getPerimeter()
   {
       return(2*(getWidth()+getHeight()));
}
  
}

//end of BetterRectangle.java

// BetterRectangleMain.java

public class BetterRectangleMain {

   public static void main(String[] args) {

       // create a rectangle with valid inputs
       BetterRectangle rect1 = new BetterRectangle(0,0,20,30);
       System.out.println("Expected area: 600.0 Actual area: "+rect1.getArea());
       System.out.println("Expected perimeter: 100.0 Actual perimeter: "+rect1.getPerimeter());
      
       // create a rectangle with invalid width
       System.out.println("Expected error message: ERROR: Width or/and height of the rectangle must be greater than 0.");
       try {
           rect1 = new BetterRectangle(0,0,-20,30);
          
       }catch(IllegalArgumentException e)
       {
           System.out.println("Actual: "+e.getMessage());
       }
      
       // create a rectangle with invalid height
       System.out.println("Expected error message: ERROR: Width or/and height of the rectangle must be greater than 0.");
       try {
           rect1 = new BetterRectangle(0,0,20,0);
          
       }catch(IllegalArgumentException e)
       {
           System.out.println("Actual: "+e.getMessage());
       }
   }
}

//end of BetterRectangleMain.java

Output: