circle3.java

来自「Java Application, Circle test」· Java 代码 · 共 56 行

package circle;
public class Circle3 extends Point2 {
   private double radius;  // Circle3's radius

   // no-argument constructor
   public Circle3()
   {
      // implicit call to Point2 constructor occurs here
   }

   // constructor
   public Circle3( int xValue, int yValue, double radiusValue )
   {
      // implicit call to Point2 constructor occurs here
      x = xValue;  // no need for validation
      y = yValue;  // no need for validation
      setRadius( radiusValue );
   }

   // set radius
   public void setRadius( double radiusValue )
   {
      radius = ( radiusValue < 0.0 ? 0.0 : radiusValue );
   }

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

   // calculate and return diameter
   public double getDiameter()
   {
      return 2 * radius;
   }

   // calculate and return circumference
   public double getCircumference()
   {
      return Math.PI * getDiameter();
   }

   // calculate and return area
   public double getArea()
   {
      return Math.PI * radius * radius;
   }

   // return String representation of Circle3 object
   public String toString()
   {
      return "Center = [" + x + ", " + y + "]; Radius = " + radius;
   }

} // end class Circle3