Creating Superclasses and Subclasses

public abstract class Shape {
    public abstract double area();
    public abstract double perimeter();
}
public abstract class Polygon extends Shape {
    public double perimeter() { return 0.0; }
    // area not implemented
}
public class Square extends Polygon {
    private double s;
    public Square(double side) { s = side; }
    public double area() { return s * s; }
}
// Usage:
Shape sh = new Square(3);
System.out.print(sh.area() + " " + sh.perimeter());

• A

  9.0 12.0

• B

  0.0 0.0

• C

  Compile error

• D

  9.0 0.0

  check_circle