圆形Shape输出面积和周长

package net.xujunjie.lesson09;

import java.util.Scanner;

public class TestCircle { public static void main(String[] args) { //声明部分 double r, c, s; Scanner sc = new Scanner(System.in); Circle circle = new Circle();

//输入部分 System.out.print("r = "); r = sc.nextDouble(); //处理部分 //设置对象属性 circle.setR(r); //调用对象 c = circle.circumference(); s = circle.area(); //输出部分 System.out.println("c = "+String.format("%.2f",c)); System.out.println("s = "+String.format("%.2f",s)); }

} package net.xujunjie.lesson09;

/**

功能：创建Circle类，实现Shape接口

2019.05.26

abstact */ public class Circle implements Shape { private double r;

public double getR() { return r; }

public void setR(double r) { this.r = r; }

@Override public double circumference() { return PI * 2 * r; }

@Override public double area() { return PI * r * r; } }