Question

public class Point
{
        protected double x, y; // coordinates of the Point

                //Default constructor
        public Point()
        {
        setPoint( 0, 0 );
        }

                //Constructor with parameters
        public Point(double xValue, double yValue )
        {
        setPoint(xValue, yValue );
        }

                // set x and y coordinates of Point
        public void setPoint(double xValue, double yValue )
        {
        x = xValue;
        y = yValue;
        }

                // get x coordinate
        public double getX()
        {
        return x;
        }

                // get y coordinate
        public double getY()
        {
        return y;
        }

                // convert point into String representation
        public String toString()
        {
        return "[" + String.format("%.2f", x)
               + ", " + String.format("%.2f", y) + "]";
        }

     //Method to compare two points
        public boolean equals(Point otherPoint)
        {
        return(x == otherPoint.x &&
               y == otherPoint.y);
        }

     //Method to compare two points
        public void makeCopy(Point otherPoint)
        {
        x = otherPoint.x;
        y = otherPoint.y;
        }

        public Point getCopy()
        {
        Point temp = new Point();

        temp.x = x;
        temp.y = y;

        return temp;
        }

                // print method
        public void printPoint()
        {
        System.out.print("[" + String.format("%.2f", x)
                       + ", " + String.format("%.2f", y) + "]");
        }

}  // end class Point

**********************************************************************************************************************************************************************

Every circle has a center and radius. Given the radius, we can determine the circle’s area and circumference. Given the center, we can determine its position in the x-y plane. The center of a circle is a point in the x-y plane. Please do the following:

1. Design the class Circle that can store the radius and the center of the circle based on the class Point (above). You should be able to perform the usual operation on a circle, such as setting radius, printing the radius, calculating and printing the area and circumference, and carrying out the usual operations on the center.
2. Write a test program to test your program.

Answer 1

//Java code

public class Point
{
    protected double x, y; // coordinates of the Point

    //Default constructor
    public Point()
    {
        setPoint( 0, 0 );
    }

    //Constructor with parameters
    public Point(double xValue, double yValue )
    {
        setPoint(xValue, yValue );
    }

    // set x and y coordinates of Point
    public void setPoint(double xValue, double yValue )
    {
        x = xValue;
        y = yValue;
    }

    // get x coordinate
    public double getX()
    {
        return x;
    }

    // get y coordinate
    public double getY()
    {
        return y;
    }

    // convert point into String representation
    public String toString()
    {
        return "[" + String.format("%.2f", x)
                + ", " + String.format("%.2f", y) + "]";
    }

    //Method to compare two points
    public boolean equals(Point otherPoint)
    {
        return(x == otherPoint.x &&
                y == otherPoint.y);
    }

    //Method to compare two points
    public void makeCopy(Point otherPoint)
    {
        x = otherPoint.x;
        y = otherPoint.y;
    }

    public Point getCopy()
    {
        Point temp = new Point();

        temp.x = x;
        temp.y = y;

        return temp;
    }

    // print method
    public void printPoint()
    {
        System.out.print("[" + String.format("%.2f", x)
                + ", " + String.format("%.2f", y) + "]");
    }

}  // end class Point

//=====================================

public class Circle {
    private double radius;
    private Point center;

    //Constructor

    public Circle(double radius, Point center) {
        this.radius = radius;
        this.center = center;
    }
    //Default Constructor
    public Circle()
    {
        radius = 0;
        center = new Point();
    }
    //getters and setters

    public double getRadius() {
        return radius;
    }

    public void setRadius(double radius) {
        this.radius = radius;
    }

    public Point getCenter() {
        return center;
    }

    public void setCenter(Point center) {
        this.center = center;
    }
    //Calculate Area
    public double getArea()
    {
        return Math.PI*radius*radius;
    }
    public double getCircumference()
    {
        return 2* Math.PI* radius;
    }
    public double getDistance()
    {
        return Math.sqrt((center.x*center.x) +(center.y*center.y));
    }

    @Override
    public String toString() {
        return "Center: "+center+" radius: "+radius;
    }
}

//============================================

public class TestCircle {
    public static void main(String[] args)
    {
        Circle circle = new Circle(10,new Point(50,60));
        System.out.println(circle);
        System.out.println("Area: "+circle.getArea());
        System.out.println("Circumference: "+circle.getCircumference());
        System.out.println("Distance from origin: "+circle.getDistance());
        System.out.println("Done....");
    }
}

//Output

//If you need any help regarding this solution ............ please leave a comment ..... thanks