public class Yuan{
public static void main(String[] args){
double r;
double area;
double zhouchang;
r = 5.5;
area = r * r * 3.14159;
zhouchang = r * 3.14159 * 2;
System.out.println("半径为" + r + "圆的面积为" + area);
System.out.println("半径为" + r + "圆的周长为" + zhouchang);
}
}
原文：http://www.cnblogs.com/xyayy/p/7504761.html