用JAVA编写一个福利彩票机选模拟器，使用随机数方法

自己写的，不懂可以问我
import java.util.Random;

import java.awt.*;

import java.awt.event.*;

public class shuangSeQiu implements ActionListener{

int i,k;
static int rm,rr;
int [] a = new int [33];
Frame f = new Frame("双色球随机数");

TextField tf = new TextField();
Random rd = new Random();
public shuangSeQiu()
{
for(i=0;i<33;i++)
{
a[i] = i;
}

f.setLayout(new BorderLayout());
f.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
}

public void init()
{

tf.addActionListener(this);

Button b = new Button("开始");
b.addActionListener(this);
f.add(tf,"North");
f.add(b);
f.setSize(300,300);
f.setVisible(true);

}

public void