Polymorphism

public abstract class Shape {
    public abstract double area();
}
public class Sq extends Shape {
    private double s;
    public Sq(double x) { s = x; }
    public double area() { return s * s; }
}
public class Tri extends Shape {
    private double b, h;
    public Tri(double bb, double hh) { b = bb; h = hh; }
    public double area() { return 0.5 * b * h; }
}
// Usage:
ArrayList<Shape> shapes = new ArrayList<Shape>();
shapes.add(new Sq(2));
shapes.add(new Tri(4, 3));
double total = 0;
for (int i = 0; i < shapes.size(); i++) {
    total += shapes.get(i).area();
}
System.out.print(total);

• A

  6.0

• B

  4.0

• C

  Compile error

• D

  10.0

  check_circle