//公式:面积 = PI*radius*radius double area = Math.PI * (radius * radius); System.out.println("The area of circle is: " + area); //公式:周长= 2*PI*radius double circumference= Math.PI * 2*radius; System.out.println(
System.out.printf("The area of Circle is %.2f, The perimeter of Circle is %.2f\n",circle.getArea(),circle.getPerimeter()); Rectangle rectangle = new Rectangle(4,6); System.out.printf("The area of Rectangle is %.2f, The perimeter of Circle is %.2f\n",rectangle.getArea(),rectangle...
public class CircleArea { //定义一个常量PI，表示圆周率 public static final double PI = 3.14;//定义一个方法，计算圆的面积，参数为半径，返回值为面积 public static double calculateArea(double radius) { //判断半径是否为正数，如果不是，返回-1表示错误 if (radius <= 0) { return -...
public class KongZhi { public static void main(String[] args) { Scanner input = new Scanner( System.in)；System.out.println("Enter a number for radius: ")；double radius = input.nextDouble()；double area= radius*radius*3.14；System.out.println("The area for the circle of r...
(1)定义一个Circle类,包含一个double型的radius属性代表圆的半径,一个findArea()方法返回圆的面积。 (2)定义一个类PassObject,在类中定义一个方法printAreas(),该方法的定义如下:publicvoidprintAreas(Cirlce c,inttimes) 在printAreas方法中打印输出1到time之间的每个整数半径值,以及对应的面积。例如,times为5,...
calcArea方法用于计算圆的面积相关知识点: 试题来源: 解析 public class Circle { double radius; public Circle(double rad) { radius = rad; } public double calcArea() { return Math.PI * radius * radius; } public static void main(String[] args) { Circle c = new Circle(3); System.out....
关键字:instanceof、this、super、static、final、package、import、abstract、interface等。 面向对象的三大特征:封装性(Encapsulation)、继承性(Inheritance)、多态性(Polymorphism)、(抽象性)。 类和对象 类(Class)和对象(Object)是面向对象的核心概念。 类是对一类事物的描述,是抽象的、概念上的定义。
接口Circlearea.java：package test;public interface Circlearea { public static double PI = 3.14;public double area(double r);} 圆类Circle.java：package test;public class Circle implements Circlearea { public double r;public Circle(double r) { this.r = r;} //圆面积 public double...
class Rectangle implements ShapeArea{ double width, height; Rectangle(double w, double h) { width=w; height=h; } public double getPerimeter() { return 2*( width+height);} public double getArea() { return width*height; } public String toString() { return "width="+width+",height="+hei...
{@Overridepublicvoidvisit(Circlecircle){doublearea=Math.PI\*circle.getRadius()\*circle.getRadius();System.out.println("Area of Circle: "+area);}@Overridepublicvoidvisit(Rectanglerectangle){doublearea=rectangle.getWidth()\*rectangle.getHeight();System.out.println("Area of Rectangle: "+area);}...