Question

用Java编写程序,从键盘输入圆的半径,求圆的周长和面积并输出

Answer 1

本人初学，答的不好的地方请见谅，程序代码如下：
import javax.swing.JOptionPane;
public class yuan{
public static void main(String args[]){
double p,s,l,r;String str;//其中s为面积，l为周长，r为半径
p=3.1415;
str=JOptionPane.showInputDialog("请输入圆的半径r");
r=Double.parseDouble(str);
l=2*p*r;
s=p*r*r;
System.out.println("圆的周长为l="+l);
System.out.println("圆的面积为s="+s);
}}

Answer 2

class Area
{
private double ans;
private double l;
private double s;
private PI=3.14;
void l(double ans)
{
l=2*ans*PI;
}
void s(double ans)
{
s=PI*ans*ans;
}
public static void main(String [] args)
{
System.out.println("please enter a number");
ans=System.in.read();
Area bb = new Area();
System.out.println(bb.l(ans));
System.out.println(bb.s(ans));
}
}