Implementing an Interface

- First, click on the class diagram then the below diagrams will be shown.
- There are two classes in the program, and it has three parts [class name, variables, function].

Fig 1

Fig 2

- Fig 1 shows the class diagram of class Point.
- Fig 2 shows the class diagram of class Driver.
- Then click on the sequence diagram which will show how the program that on the left side is executed.

Sequence diagram

Following steps are explaining sequence diagram.

- The diagram defines a class called Point with two private instance variables: x and y, which represent the coordinates of a point in a 2D plane.
- The Point class has four private methods.
- setX(int xCoord) sets the value of the x coordinate.
- setY(int yCoord) sets the value of the y coordinate.
- getX() returns the value of the x coordinate.
- getY() returns the value of the y coordinate.
- Next, an interface named Shape is defined. It includes the following.
- A public static final constant pi with a value of 3.14.
- Two abstract methods: area() and perimeter(), which any class implementing this interface must provide concrete implementations for.
- The code then defines a class named Circle which implements the Shape interface.
- The Circle class has a protected instance variable radius to store the radius of the circle.
- The constructor Circle(double r) initializes the radius with the given value r.
- The area() method calculates and returns the area of the circle using the formula: pi * radius * radius.
- The perimeter() method is not defined properly in the code. It seems like there's a typo with the variable p, and it's missing a return statement. It should be fixed to properly calculate and return the perimeter of the circle using the formula: 2 * pi * radius.
- Inside the main method, an instance of the Circle class is created with a radius of 5.
- The area() method of the Circle class is called to calculate the area of the circle.
- The perimeter() method of the Circle class is called to calculate the perimeter of the circle.
- The results are then printed to the console using System.out.println().

- There are two buttons [Class Diagram and Sequence Diagram] on the right side of the simulation.
- First, click on the Class Diagram then the class diagrams will be shown.
- Then click on the Sequence Diagram, it will display two buttons – Previous and Next.
- The Next button shows the next sequence, and the Previous button shows the previous sequence.
- After all the sequence diagrams the result box will be shown.
- Click on the Reset button to redo the simulation.