import java.io.*;
//定义一个圆类(Circle),在类中定义成员变量(圆心的横纵坐标,半径,常量π)
//构造方法和普通的成员方法(输出圆心和半径信息的方法,求周长的方法,求面积的方法
class Circle{
private double x_axis,y_axis,radius;
public static double PI = 3.14159;
Circle(double x,double y,double r){
x_axis = x;
y_axis = y;
radius = r;
}
Circle(){
x_axis = 0;
y_axis = 0;
radius = 0;
}
public void getInfo(){
System.out.println("x_axis:"+ x_axis );
System.out.println("y_axis:" + y_axis );
System.out.println("radius:" + radius );
}
public double getCircum(){
return 2*PI*radius;
}
public double getArea(){
return PI*radius*radius;
}
}
class Test6{
public static void main(String[] args){
Circle a = new Circle(1,2,3);
a.getInfo();
System.out.println("zhouchang:"+ a.getCircum() );
System.out.println("mianji:"+ a.getArea() );
Circle b= new Circle();;
b.getInfo();
}
}
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