Java学习之定义一个名为Cylinder类表示圆柱，它继承Circle类，要求定义一个变量height表示圆柱高度。

约定不等于承诺〃 2023-01-13 09:56 114阅读 0赞

**案例介绍：**

（1）定义一个名为Cylinder类表示圆柱，它继承Circle类，要求定义一个变量height表示圆柱高度。覆盖getArea()方法求圆柱的表面积，定义getVolume()方法求圆柱体，定义默认构造方法和带radius和height两个参数的构造方法。

（2）编写测试程序，提示用户输入圆柱的底面圆的半径和高度，程序创建一个圆柱对象，计算并输出圆柱表面积和体积。

**Cylinder类代码：**

import java.util.Scanner;
    public class Cylinder extends Circle{
        
    	private double height;
    	public Cylinder(){
        }
    	public Cylinder (double radius, double height) {
        
    		this. radius = radius;
    		this.height = height;
    	}
    	@Override
    	public double getArea(){
        
    		double area = getPerimeter() * height + radius * radius * 3.14 * 2;
    		return area;
    	}
    	public double getVolume(){
        
    		return super.getArea() * height;
    	}
    	public static void main(String[] args){
        
    		double radius, height;
    		Scanner input = new Scanner(System.in);
    		System.out. println("请输入圆柱的底面半径:");
    		radius =input. nextDouble() ;
    		System. out. println("请输人圆柱的高:");
    		height = input.nextDouble();
    		Cylinder c = new Cylinder(radius,height) ;
    		System.out.println("圆柱表面积是:"+ c. getArea());
    		System.out.println("圆柱体积是:"+ c.getVolume());
    	}
    }

**Circle类代码：**

public class Circle {
        
    		double centerX;
    		double centerY;
    		double radius;
    		public Circle(){
        
    		this(1.0);
    		}
    		public Circle(double radius){
        
    			
    		this.radius = radius;
    		}
    		public double getRadius(){
        
    		return radius;
    		}
    		public void setRadius(double radius){
        
    		this.radius = radius;
    		}
    		public double getArea(){
        
    			double area = 3.14 * radius *radius;
    			return area;
    		}
    		public double getPerimeter(){
        
    			double perimeter = 2 * 3.14 * radius;
    			return perimeter;
    		}
    		public static void main(String[] args){
        
    			Circle c = new Circle();
    			System.out.println(c.getRadius());
    			c.setRadius(10);
    			System.out.println(c.getArea());
    			System.out.println(c.getPerimeter());
    		}
    	}

**案例运行图：**  
![在这里插入图片描述][20210417201215509.png_pic_center]

[20210417201215509.png_pic_center]: /images/20221022/306a3fa99cc145c8b6b9bcec13a48733.png