circle.java

java课件

public class Circle {
  /** The radius of the circle */
  private double radius;

  /** Construct a circle with radius 1 */
  public Circle() {
    radius = 1.0;
  }

  /** Construct a circle with a specified radius */
  public Circle(double radius) {
    this.radius = radius;
  }

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

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

  /** Return the area of this circle */
  public double findArea() {
    return radius * radius * Math.PI;
  }
}