编写一个输入圆半径，输出圆的周长和面积的java applet程序，代码大概十几二十行，希望用scanner输入

Answer 1

import java.awt.FlowLayout;
import java.awt.Label;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;

import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JTextField;

public class Test extends JApplet{
private double r;
private JTextField tf = new JTextField(20);
private JButton cal = new JButton("计算");
private Label l = new Label("");

public Test() {
setSize(500, 300);
setLayout(new FlowLayout());
add(new Label("输入半径："));
add(tf);
add(cal);
add(l);
cal.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent arg0) {
r = Double.valueOf(tf.getText());
double zc = r*2*Math.PI;
double s = Math.PI*r*r;
DecimalFormat df = new DecimalFormat("#.00");
String zcString = df.format(zc);
String sString = df.format(s);
l.setText("面积：" + sString);
l.setText(l.getText() + "周长：" + zcString);
}
});
}

/**
* @param args
*/
public static void main(String[] args) {
Test t = new Test();
}

}