/** Inheritance demo. @author Jed Yang, 2018-01-10 */ public class Circle extends Shape { // instance variables, private private String name; private int radius; public Circle(String name, int radius) { this.name = name; this.radius = radius; } public Circle() { this("circle", 10); } @Override public double getArea() { return Math.PI * Math.pow(radius, 2); } public double getPerimeter() { return 2 * Math.PI * radius; } // Often automatically called. Like Python's __str__ magic method. public String toString() { return name + " of radius " + radius; } }