class Shape {
public double area() {
return 0;
}
}
class Rectangle extends Shape {
private double length;
private double width;
public Rectangle(double length, double width) {
this.length = length;
this.width = width;
}
@Override
public double area() {
return length * width;
}
}
interface Shape {
double area();
}
class Rectangle implements Shape {
private double length;
private double width;
public Rectangle(double length, double width) {
this.length = length;
this.width = width;
}
@Override
public double area() {
return length * width;
}
}
class Circle implements Shape {
private double radius;
public Circle(double radius) {
this.radius = radius;
}
@Override
public double area() {
return Math.PI * radius * radius;
}
}