package qiuyuan;
public class Yuan1
{
public static void main(String[] args)
{
int r=3;
final double PI=3.14;
double z=PI*2*r;
double s=PI*Math.pow(3,2);
System.out.println("元旦周长z="+z);
System.out.println("元旦面积s="+s);
}
}
原文：http://www.cnblogs.com/liuyanzeng/p/5860211.html