java爪哇小程序----编写一个和圆相关的类

class Circle{
private double radius;
Circle(double r){
radius=r;
}
Circle(){        //构造方法部分
radius=1;
}
Circle(Circle c){
radius=c.radius;
}
public double getRadius(){
return radius;
}
public double getCirc(){
double t;
t=Math.PI*2*radius;
return t;
}
public double getArea(){
double t;
t=Math.PI*radius*radius;
return t;
}
}

class Example01{
public static void main(String arg[]){
Circle c1=new Circle();
Circle c2=new Circle(5);
Circle c3=new Circle(c1);
System.out.println(c1.getCirc());
System.out.println(c2.getCirc());
System.out.println(c3.getCirc());
}
}