Public class CirdeAndsquare{
public static void main(string[] args){
double r = 5.5;
double c = 2*Math.PI*r;
double s = r*r*Math.PI;
System.out.println("圆的周长是:"+c);
System.out.println("圆的面积是:"+s);
}
}
原文：http://www.cnblogs.com/huiiuh/p/7526559.html