如何在surfaceMeanSize中调用Cone方法中的radius？public class Cone extends GraphicObject{ public Cone(ObjectColor color, double radius, double length) { } @Override public double surfaceMeanSize() { return Math.PI * () } @Override public double volume() { return 0; }

您可以将Cone类中的radius作为属性保存，并将其传递给surfaceMeanSize()方法。在这种情况下，您可以使用以下代码：

public class Cone extends GraphicObject{

private double radius;
private double length;

public Cone(ObjectColor color, double radius, double length) {
this.radius = radius;
this.length = length;
}

@Override
public double surfaceMeanSize() {
double slantHeight = Math.sqrt(Math.pow(radius, 2) + Math.pow(length, 2));
return Math.PI * radius * slantHeight;
}

@Override
public double volume() {
return 0;
}
}

在这个例子中，我们使用了Cone类的构造函数来设置radius和length属性，并在surfaceMeanSize()方法中使用它们计算圆锥的表面积。

相关问题

运行如下代码： class COne { public void f() { System.out.println("COne.f"); } } class CTwo extends COne{ public void f() { System.out.println("CTwo.f"); } } class CThree { public void g(COne one) { System.out.println("g(Cone)"); one.f(); } public void g(CTwo two) { System.out.println("g(Ctwo)"); two.f(); } } public class Main { public static void main(String[] args) { COne one = new CTwo(); CThree three = new CThree(); three.g(one); } } 控制台输出的结果是( )。 A. g(Cone) CTwo.f B. g(Cone) COne.f C. g(Ctwo) CTwo.f D. g(Ctwo) COne.f

答案是 C. g(Ctwo) CTwo.f。因为在 main 函数中，创建了一个 CTwo 类型的对象 one，并将其赋值给了 COne 类型的变量 one。然后，创建了一个 CThree 类型的对象 three，并调用了它的 g 方法，传入了 one。由于 one 是 CTwo 类型的对象，所以会调用 g(CTwo two) 方法，输出 g(Ctwo) 和 CTwo.f。

complete abstract class GraphicObject and implement subclasses Cone , Cuboid and Sphere based on the class GraphicObject .

Here is an example implementation of the abstract class GraphicObject and its subclasses Cone, Cuboid, and Sphere:

abstract class GraphicObject {
    protected int x, y;

    public GraphicObject(int x, int y) {
        this.x = x;
        this.y = y;
    }

    abstract double area();
    abstract double perimeter();
}

class Cone extends GraphicObject {
    private int radius;
    private int height;

    public Cone(int x, int y, int radius, int height) {
        super(x, y);
        this.radius = radius;
        this.height = height;
    }

    @Override
    double area() {
        return Math.PI * radius * (radius + Math.sqrt(Math.pow(height, 2) + Math.pow(radius, 2)));
    }

    @Override
    double perimeter() {
        return 2 * Math.PI * radius;
    }
}

class Cuboid extends GraphicObject {
    private int length;
    private int width;
    private int height;

    public Cuboid(int x, int y, int length, int width, int height) {
        super(x, y);
        this.length = length;
        this.width = width;
        this.height = height;
    }

    @Override
    double area() {
        return 2 * (length * width + width * height + height * length);
    }

    @Override
    double perimeter() {
        return 4 * (length + width + height);
    }
}

class Sphere extends GraphicObject {
    private int radius;

    public Sphere(int x, int y, int radius) {
        super(x, y);
        this.radius = radius;
    }

    @Override
    double area() {
        return 4 * Math.PI * Math.pow(radius, 2);
    }

    @Override
    double perimeter() {
        return 2 * Math.PI * radius;
    }
}

The abstract class `GraphicObject` defines the common properties and methods that all subclasses must implement. The `Cone`, `Cuboid`, and `Sphere` classes extend the `GraphicObject` class and provide their own implementations of the `area()` and `perimeter()` methods.

For example, the `Cone` class calculates the surface area and circumference of a cone based on its radius and height, while the `Cuboid` class calculates the surface area and perimeter of a rectangular cuboid based on its length, width, and height. The `Sphere` class calculates the surface area and circumference of a sphere based on its radius.

Note that the `GraphicObject` class is abstract and cannot be instantiated directly. Instead, it provides a template for creating subclasses that represent specific types of geometric objects.