编写一个计算器的代码,以下代码仅算了加法!


import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
public class jisuan extends Applet implements ActionListener
{    
     public  int c=0;
     public  int  a=0;
     public int w=0;
     Button b[];
     String names[]={"0","1","2","3","4","5","6","7","8","9",".","+","-","*","/","=","clear"};
     TextField text1;
     public void init()
      {
         text1=new TextField();
         text1.addActionListener(this);
         add(text1);
         setLayout(new GridLayout(5,3,5,5));
         b=new Button[names.length];
         for(int i=0;i<names.length;i++)
         {
           b[i]=new Button(names[i]);
           b[i].addActionListener(this);
           add(b[i]);
         }
     }                                               //显示计算器上最基本的按钮     
     public void actionPerformed(ActionEvent e)
     {
         
          for(int i=0;i<b.length;i++)
          if(e.getSource()==b[i])
             {
                if(i<=9)
                  {
                     text1.setText(text1.getText()+Integer.toString(i));
                      a=Integer.parseInt(text1.getText());             //保存第一次输入的数值  
                                       
                  }
                else if(i==10) text1.setText(text1.getText()+".");
                   else if(i==11)
                  {
                   c=11;                         //判断是否是加号
                   w=a;
                   text1.setText(" ");
                  }
               
                else if(i==15)
                {   
                   if(c==11)
                    { 
                                                               
                    text1.setText(Integer.toString(Integer.parseInt(w+a)); //是加法然后进行计算
                     w=0;
                   }  
                                                               
                }
                else if(i==16) text1.setText(" ");
                validate();
             }
     }
    
}