class A{
  final double PI = 3.1415926;
  public double  getArea(final double r){
    return PI*r*r;
  }
  public final void speak(){
    System.out.println("您好,how's everthing here?");
  }
}
public class Example5_9{
  public static void main(String args[]){
    A a = new A();
    System.out.println("面积:"+a.getArea(100));
    a.speak();
  }
}