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 : Solid
{
 private double radius;
//constructor
 public Sphere(String sphereName, double sphereRadius) : base(sphereName)
 {
   radius = sphereRadius;
 }
 public override double volume()
 { return (4.0/3.0) * Math.PI * radius * radius * radius; }
 }
public class RectangularPrism : Solid
{
 private double length;
 private double width;
 private double height;
//constructor
 public RectangularPrism(String prismName, double l, double w, double h) :  base(prismName)
 {
   length = l;
   width = w;
   height = h;
 }
 public override 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);
   Random rnd = new Random();
   int flipCoin = (int) (rnd.Next(2)); //0 or 1
   if (flipCoin == 0)
    sol = sph;
   else
    sol = rec;
   printVolume(sol);
 }
}