Re: doubt

Hi,
I am trying to do a program with functionalities of a simple
calculator...The program I have done is given below.After compilation
when I execute the file ,and click on to the button ,nothing
works.Please give me a tip to correct my program.

class handler implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String str1=null,str2=null,str3=null,str4=null;
int x,y,z=0;
while(e.getSource()!=equal)
{

if(e.getSource()==one)
str1=str1+"1";
else if(e.getSource()==two)
str1=str1+"2";
else if(e.getSource()==three)
str1=str1+"3";
else if (e.getSource()==four)
str1=str1+"4";
else if(e.getSource()==five)
str1=str1+"5";
else if(e.getSource()==six)
str1=str1+"6";
else if(e.getSource()==seven)
str1=str1+"7";
else if(e.getSource()==eight)
str1=str1+"8";
else if(e.getSource()==nine)
str1=str1+"9";
else if(e.getSource()==zero)
str1=str1+"0";
else if(e.getSource()==plus)
{
str3="+";
str2=str1;
str1=null;
}
else if(e.getSource()==minus)
{
str3="-";
str2=str1;
str1=null;
}
else if(e.getSource()==star)
{
str3="*";
str2=str1;
str1=null;
}
else if(e.getSource()==div)
{
str3="/";
str2=str1;
str1=null;
}
textBox.setText(str1);

  }

public class Calculator
{
public static void main(String args[])
{
test obj = new test();
obj.setSize(450,350);
obj.setLayout(new FlowLayout());

obj.setVisible(true);

obj.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}
}