JAVA抽象类与接口( 十 )

public double getSrea() {

f=3.1415926*radius*radius;

return f;

public double getPerimeter() {

double d=4*3.1415926*radius;

return d;

public class test2 {

public static void main(String[
ages){

Circle d=new Circle();

d.getSrea();

d.getPerimeter();

d.to();

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