circle9.java

java课件

// Circle9.java: The circle class that extends GeometricObject
public class Circle9 extends GeometricObject {
  private double radius;

  /** Construct a circle with default properties */
  public Circle9() {
    this(1.0);
  }

  /** Construct a circle with a specified radius */
  public Circle9(double radius) {
    this(radius, "white", false);
  }

  /** Construct a circle with specified radius, filled, and color */
  public Circle9(double radius, String color, boolean filled) {
    super(color, filled);
    this.radius = radius;
  }

  /** Return radius */
  public double getRadius() {
    return radius;
  }

  /** Set a new radius */
  public void setRadius(double radius) {
    this.radius = radius;
  }

  /** Implement the findArea method defined in GeometricObject */
  public double findArea() {
    return radius * radius * Math.PI;
  }

  /** Implement the findPerimeter method defined in GeometricObject*/
  public double findPerimeter() {
    return 2 * radius * Math.PI;
  }

  /** Override the toString() method defined in the Object class */
  public String toString() {
    return "[Circle] radius = " + radius;
  }
}