java編寫一個環形類？

public class Circle{

public static final double pie=3.14;

public static double area1(double r)

{

return pie*r*r;

}

public static double area2(double r)

{

return pie*r*r;

}

public static double circleArea()

{

return Circle.area1(圓1的半徑)-Circle.area2(圓2的半徑);

}

}

最后在主方法調用即可