帮忙用java写一个程序，在线等

public class Circle{

private static double r;//静态变量 圆的半径
public double PI=3.142;
public Circle(double r){
Circle.r=r;
}

public double zhouchang(){
return 2*PI*r;
}
public static double getR() {
return r;
}
public static void setR(double r) {
Circle.r = r;
}
public double mianji(){
return PI*r*r;
}
public static void main(String[] args) {
Circle circle=new Circle(4);
System.out.println("半径为"+Circle.getR()+"的周长为"+circle.zhouchang());
System.out.println("半径为"+Circle.getR()+"的面积为"+circle.mianji());
}
}

这么简单的问题也问别人。。你的技术哪辈子才能长进啊

目测 该同学在考试。。

class Circle{
static double r ;
final double PI=3.142;
public void zouchang(){
zouchang c=new zouchang();
c=2 * PI * r;
System out println( “c”);
}
public void mianji(){
mianji s=new mianji();
s= PI * r * r;
System out println( “s”);
}
class C3 extends Circle{
public void main (Sting args[]){
double r=2.0;
System.out.println(“c” ,”s”);
}