java計算圓的面積和周長

public class Circle{
 private float radius;
 public Circle(){
  this.radius=5.0f;
 }
 public Circle(float radius){
  this.radius=radius;
 }
 public void Area(){
  System.out.println("半徑為"+this.radius+"面積是："+(3.14*radius*radius));
 }
 public void Circumference(){
  System.out.println("半徑為"+this.radius+"周長是:"+(3.14*2*radius));
}

public static void main(String arg[]){
 Circle c1=new Circle();
 c1.Area();
 c1.Circumference();
 Circle c2=new Circle(9.0f);
 c2.Area();
 c2.Circumference();
}
}