Çàäà÷à . 18

public abstract class Solid
{
 private String name;
//constructor
 public Solid(String solidName)
 { name = solidName; }
 public String getName()
 { return name; }
 public abstract double volume();
}
public class Sphere extends Solid
{
 private double radius;
//constructor
 public Sphere(String sphereName, double sphereRadius)
 {
  super(sphereName);
  radius = sphereRadius;
 }
 public double volume()
 { return (4.0/3.0) * Math.PI * radius * radius * radius; }
}
public class RectangularPrism extends Solid
{
 private double length;
 private double width;
 private double height;
//constructor
 public RectangularPrism(String prismName, double l, double w,
double h)
 {
 super(prismName);
 length = l;
 width = w;
 height = h;
 }
 public double volume()
 { return length * width * height; }
}

public class SolidMain
{
/** Output volume of Solid s. */
 public static void printVolume(Solid s)
 {
 System.out.println("Volume = " + s.volume() + " cubic units");
 }
 public static void main(String[] args)
 {
 Solid sol;
 Solid sph = new Sphere("sphere", 4);
 Solid rec = new RectangularPrism("box", 3, 6, 9);
 int flipCoin = (int) (Math.random() * 2); //0 or 1
 if (flipCoin == 0)
  sol = sph;
 else
  sol = rec;
 printVolume(sol);
 }
}