設(shè)計(jì)一個(gè)圓類，提供有參無參兩個(gè)構(gòu)造方法來初始化類的成員變量，提供圓面積的功能；在主函數(shù)中產(chǎn)生兩個(gè)對(duì)象實(shí)例，從鍵盤流得到的數(shù)據(jù)作為圓的半徑值，分別調(diào)用有參無參構(gòu)造方法，在控制臺(tái)輸出兩個(gè)對(duì)象的面積。import java.util.Scanner;public class Circles(){?? private double r;final static double PI=3.14;public Circles(double r){? this.r=r;}public void? setR(double r){?this.r=r;}public double getR(){?return r;}Circles(){}public double getArea(){return PI*r*r;}public static void main(String[] args){?Scanner s1=new Scanner(System.in);System.out.print("r1=");Circles n1=new Circles(s1.nextDouble());System.out.println("S1="+n1.getArea());Scanner s2=new Scanner(System.in);System.out.print("r2=");Circles n2=new Circles(s2.nextDouble(r2));?System.out.println("S2="+n2.getArea());}}有一個(gè)錯(cuò)