java小程序——简单计算器

import java.applet.Applet;
import java.awt.Button;
import java.awt.Label;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.sound.sampled.AudioInputStream;
import javax.swing.JButton;
import com.sun.media.sound.Toolkit;

public class c extends Applet implements ActionListener {
	/**
	 * @param args
	 */
	Label res,res2,res3;
	TextField firstnum,secondnum,result;
	Button b1,b2,b3,b4,clear,re;
	int test,z;
	public void init()
	{
		firstnum=new TextField(30);
		secondnum=new TextField(30);
		result =new TextField(30);
		res =new Label("第一个整数");
		res2=new Label("第二个整数");
		res3=new Label("计算结果：");
		setLayout(null);//关闭默认管理布局
		add(res);
		res.setBounds(0,0,70,30);
		add(res2);
		res2.setBounds(0,30,70,30);
		add(res3);
		res3.setBounds(0,70,70,30);
		add(firstnum);
		firstnum.setBounds(80,10,80,20);
		add(secondnum);
		secondnum.setBounds(80,40,80,20);
		add(result);
		result.setBounds(80,75,80,20);
		b1= new Button("+");
		b2= new Button("-");
		b3= new Button("*");
		b4= new Button("/");
		re= new Button("=");
		clear= new Button("clear");
		add(re);
		re.setBounds(30,100,35,25);
		add(clear);
		clear.setBounds(80,100,35,25);
		add(b1);
		b1.setBounds(10,140,25,20);
		add(b2);
		b2.setBounds(45,140,25,20);
		add(b3);
		b3.setBounds(80,140,25,20);
		add(b4);
		b4.setBounds(115,140,25,20);
		b1.addActionListener(this);
		b2.addActionListener(this);
		b3.addActionListener(this);
		b4.addActionListener(this);
		re.addActionListener(this);
		clear.addActionListener(this);
	}
	public void actionPerformed(ActionEvent  e)
	{
		//JButton t=(JButton) e.getSource();
		if(e.getActionCommand().equals("+"))
			test=1;
		if(e.getActionCommand().equals("-"))
			test=2;
		if(e.getActionCommand().equals("*"))
			test=3;
		if(e.getActionCommand().equals("/"))
			test=4;
		if(e.getActionCommand().equals("="))
		{
			int x=Integer.parseInt(firstnum.getText());
			int y=Integer.parseInt(secondnum.getText());
			boolean flag=false;
			switch(test)
			{
			case 1:
				z=x+y;
				break;
			case 2:
				z=x-y;
				break;
			case 3:
				z=x*y;
				break;
			case 4:
				if(y==0)
					flag=true;
				else 
					z=x/y;
				break;
				default:
					flag=true;
			}
			if(flag==true)
				result.setText("0");
			else 
				result.setText(Integer.toString(z));
		}
		if(e.getActionCommand().equals("clear"))
		{
			firstnum.setText("");
			secondnum.setText("");
			result.setText("");
		}
	}
}