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

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.

1.写一个锥体的泛型类Cone<E>，泛型E为它的底面，Cone可以设置高度和计算体积。然后定义一个泛型Circle。在主类中让Circle作为Cone<E>的底面，并计算Cone<E>的体积。使用java编写

好的，下面是代码实现：

定义泛型类Circle：

public class Circle<T extends Number> {
    private T radius;

    public Circle(T radius) {
        this.radius = radius;
    }

    public T getRadius() {
        return radius;
    }

    public void setRadius(T radius) {
        this.radius = radius;
    }
}

定义泛型类Cone：

public class Cone<E extends Circle<? extends Number>> {
    private E bottom;
    private Number height;

    public Cone(E bottom, Number height) {
        this.bottom = bottom;
        this.height = height;
    }

    public E getBottom() {
        return bottom;
    }

    public void setBottom(E bottom) {
        this.bottom = bottom;
    }

    public Number getHeight() {
        return height;
    }

    public void setHeight(Number height) {
        this.height = height;
    }

    public double getVolume() {
        double r = bottom.getRadius().doubleValue();
        double h = height.doubleValue();
        return 1.0 / 3.0 * Math.PI * r * r * h;
    }
}

在主函数中使用Circle作为Cone的底面并计算体积：

public class Main {
    public static void main(String[] args) {
        Circle<Double> circle = new Circle<>(2.0);
        Cone<Circle<Double>> cone = new Cone<>(circle, 4.0);
        System.out.println("Cone Volume: " + cone.getVolume());
    }
}

输出结果：Cone Volume: 16.755160819145562

注意：这里的泛型类Cone的底面必须是Circle的子类，而Circle的泛型参数必须是Number的子类，因为在计算体积时需要进行类型转换。