一个java报的错，求大佬解答

Question

import java.lang.Math;
import java.util.Scanner;
public class test2{
  public static void main(String [] args){
    Scanner sc = new Scanner(System.in);
    Circle [] p = new Cylinder[5];
	Circle temp = new Cylinder(1,3);
	
	for(int i=0;i < 5;i++){
	  double m,n;
	  System.out.println("请输入半径");
	  m = sc.nextDouble();
	  System.out.println("请输入高");
	  n = sc.nextDouble();
	  p[i] = new Cylinder(m,n);
	}
	
//排序************	
	for(int m=0;m < 5;m++){
	  for(int i=0;i < 5;i++){
	    if(p[m].compareVolume(p[i]) < 0){
		temp = p[m];
	    p[m] = p[i];
		p[i] = temp;
		}
	  }
	}
//***************	
//输出***************
	for(int i=0;i < 5;i++){
	System.out.println("圆柱体底面圆的半径:  " + p[i].getRadius());
	System.out.println("圆的面积:  " + p[i].getArea(p[i].getRadius()));
	System.out.println("圆的周长:  " + p[i].getPerimeter(p[i].getRadius()));
	System.out.println("圆柱体的体积:  " + p[i].getPerimeter(p[i].getArea(p[i].getRadius())));
	}
//*******************	
  }
}
//*****************************************
class Circle{
   private double Radius;
   
   public Circle(){
     Radius = 0;
   }
   
   public Circle(double  r ){
     Radius = r;
   }
   
   public void setRadius(double r){
     Radius = r;
   }
   
   public double getRadius(){
     return Radius;
   }
   
   public double getArea(double r){
     return Math.PI * r * r;
   }
   
   public double getPerimeter(double r){
     return 2 * Math.PI * r;
   }
   
   public void show(){
     System.out.println("圆的面积： " + this.getArea(Radius));
     System.out.println("圆的周长： " + this.getPerimeter(Radius));
   }
}
//**************************************
class Cylinder extends Circle {
    private double height;
 
    public Cylinder (double r, double h){
        super(r);
        this.height = h;
    }
 
    public double getVolume() {
        return Math.PI * super.getRadius() * super.getRadius() * height;
    }
 
    public double compareVolume(Cylinder another){
	    return (this.getVolume() - another.getVolume());
	}
	
	public double getArea(double r){
	    return 2 * super.getArea(r);
	}
	
    public void showVolume( ){
	   System.out.println("圆柱体的高：" + this.height);
	   System.out.println("圆柱体的半径：" + super.getRadius());
	   System.out.println("圆柱体的体积：" + this.getVolume());
       System.out.println("圆柱体的底面积：" + this.getArea(this.getRadius()));
    }
}

Answer 1

Cylinder [] p = new Cylinder[5];
Cylinder temp = new Cylinder(1,3);

改成子类吧。compareVolume方法是子类独有的方法。