What I want to achieve ： To design a Shape Interface and its two implementation classes Square and Circle. Requirements are as follows ：
Shape There is an abstract method in the interface area（）, The receive method has a double Parameters of type , Return to one double Result of type .
Square and Circle Implemented in the Shape Interface area（） Abstract method , Find the area of a square and a circle respectively and return .
Create... In the test class Square and Cirecle object , And calculate the side length as 2 The area and radius of the square are 3 Circular area of .
Take the answer ：
Give me an example , You don't have to write the constructor ：
interface Shape{ public double area(double n);}class Square implements Shape{ double edge; public Square(double edge){ this.edge = edge; } @Override public double area(double n) { return n*n; }}class Circle implements Shape{ double radius; public Circle(double radius){ this.radius = radius; } @Override public double area(double n) { return Math.PI*n*n; }}public class TestShape{ public static void main(String[] args) { Square s = new Square(2); Circle c = new Circle(3); System.out.println(" Square area ："+s.area(2)); System.out.println(" Circular area ："+c.area(3)); }}版权声明
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