Here is the file Circle.java, implementing the Circle class:


// Circle.java: model a rectangle object
public class Circle
{ 
   // data fields for the object
   private double radius;
   private double xCoordCenter;
   private double yCoordCenter;
   private String name;
   private int idNumber;
   private static int counter = 1000; // used to give unique idNumber

   // constructor initializes fields from input parameters
   public Circle(double initialRadius, double initialXCoordCenter,
       double initialYCoordCenter, String initialName)
   {
      radius = initialRadius;
      xCoordCenter = initialXCoordCenter;
      yCoordCenter = initialYCoordCenter;
      name = initialName;
      idNumber = ++counter;
   }

   //accessor methods
   public String toString( )
   {
      return "[name: \"" + name + "\", ID Number:" + idNumber +
            ", Radius:" + radius +
            ", Center: (" + xCoordCenter + ", " + yCoordCenter +
            "),\n\t Area:" + getArea() +
            ", Circumference: " + getCircumference() + "]";
   }

   public String getName( )
   {
      return name;
   }

   public int getIdNumber( )
   {
      return idNumber;
   }

   public double getArea( )
   {
      return Math.PI*radius*radius;
   }

   public double getRadius( )
   {
      return radius;
   }

   public double getXCoordCenter( )
   {
      return xCoordCenter;
   }

   public double getYCoordCenter( )
   {
      return yCoordCenter;
   }

   public double getCircumference( )
   {
      return 2*Math.PI*radius;
   }
}

Here is the file CircleTest.java, that tests the Circle class:


// CircleTest.java: class with main() to test Circle
public class CircleTest
{
   public static void main (String[] args)
   {
      // Create a circle, radius 10, center (2,3) called "Fancy"
      Circle aCircle = new Circle(10, 2, 3, "Fancy");
      System.out.println("aCircle=" + aCircle);
                
      // Test the get accessor methods of Circle 
      System.out.println("The Name of aCircle: \"" +
                     aCircle.getName() + "\""); 
      System.out.println("The ID Number of aCircle: \"" +
                     aCircle.getIdNumber() + "\""); 
      System.out.println("The Radius of aCircle: " +
                     aCircle.getRadius()); 
      System.out.println("The Circumference of aCircle: " +
                     aCircle.getCircumference());
      System.out.println("The Area of aCircle: " +
                     aCircle.getArea());
      System.out.println("The Center of aCircle: (" +
                     aCircle.getXCoordCenter() + ", " +
                     aCircle.getYCoordCenter() + ")");
      System.out.println();
      Circle anotherCircle = new Circle(5, -2, 4, "Smaller");
      System.out.println("anotherCircle=" + anotherCircle);
   }
}

Here is sample program output:


aCircle=[name: "Fancy", ID Number:1001, Radius:10.0, Center: (2.0, 3.0),
         Area:314.1592653589793, Circumference: 62.83185307179586]
The Name of aCircle: "Fancy"
The ID Number of aCircle: "1001"
The Radius of aCircle: 10.0
The Circumference of aCircle: 62.83185307179586
The Area of aCircle: 314.1592653589793
The Center of aCircle: (2.0, 3.0)

anotherCircle=[name: "Smaller", ID Number:1002, Radius:5.0, Center: (-2.0, 4.0),
         Area:78.53981633974483, Circumference: 31.41592653589793]