/*****
* 定义一个类，描述圆的特性
* @author yanlong
* 2017/5/5
*/
package java4;
public class liti4_1 {
private int x;
private int y;
private static int r;
public int getR() {
return r;//获取半径
}
public void setR(int r) {
this.r = r;
}
public float getArea(){
return (float)Math.PI*r*r;
}
public static void main(String[] aargs){
//初始化一个圆
liti4_1 a=new liti4_1();
a.x=10;
a.y=10;
a.setR(2);
float Area=a.getArea();
System.out.println("圆的半径："+r);
System.out.printf("圆的面积"+Area);
}
}