计算器

package mycounter;


import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.math.*;
import java.lang.Integer;
public class counter extends JFrame implements ActionListener {
JFrame Jf=new JFrame("Mycounter"); 
JPanel Jp1=new JPanel();
JPanel Jp2=new JPanel();
JTextField Jtf=new JTextField(25);
String str[]={"sin","1","2","3","+","cos","4","5","6","-","tan","7","8","9",
"*","Int","0",".","=","/"}; 
JButton JBu;
String operator=null;
String num,s;
double one;
static double two=0;
boolean bool=true;


public counter()
{
init();
}
public void init()
{   
Jf.setBounds(500,200,300,240);
    Jf.setLayout(new BorderLayout());

    Jtf.setVisible(true);
Jp1.add(Jtf);
Jp1.setVisible(true);
Jf.add(Jp1,BorderLayout.NORTH);

    Jp2.setLayout(new GridLayout(4,5,1,1));
    for(int i=0;i<20;i++)
{
JBu=new JButton(str[i]);
   JBu.addActionListener(this);
Jp2.add(JBu);
}
    Jp2.setVisible(true);
    Jf.add(Jp2,BorderLayout.CENTER);
    
    Jf.setVisible(true);
}
public void actionPerformed( ActionEvent e)
{
   s=e.getActionCommand();
   if(s.charAt(0)=='0')
   {
  if(!bool&&s!="=")
  {
Jtf.setText(Jtf.getText()+s);  
  }
  else if(operator!=null)
  {
  Jtf.setText(s);
  num = Jtf.getText();
  two=0;
  operator=null;
  }


   }
   else if('1'<=s.charAt(0)&&s.charAt(0)<='9')
{  
  if(!bool)
  { 
  Jtf.setText(Jtf.getText()+s);
  }
  else
  {
  Jtf.setText(s);
  }
bool=false;
    }
   else if(s==".")
   {
  if(Jtf.getText().indexOf(".")==-1)
  {

   if(Jtf.getText()==null)
{
Jtf.setText("0.");
}
   else if(!bool)   
{
Jtf.setText(Jtf.getText()+s);
}
bool=false;
  }
   }
   else if(s=="sin"||s=="cos"||s=="tan"||s=="Int")
   {
  num=Jtf.getText();
  operation1();
   }
   else if(s=="=")
   {
  operation();
   }
   else
   {
  if(operator!=null)
  operation();
  else
  {  operator=s;
  num=Jtf.getText();
  Jtf.setText("");
        }
   }
}
public void operation1()
{
one=Double.parseDouble(num);
   if(s=="sin")
   {
Jtf.setText(""+Math.sin(one));
   }
   if(s=="cos")
   {
Jtf.setText(""+Math.cos(one));
   }
   if(s=="tan")
   {
Jtf.setText(""+Math.tan(one));
   }
   if(s=="Int")
   {
  int i=(int)one;
//  System.out.println(i);
  Jtf.setText(""+i);
   }
}
public void operation()
{
one=Double.parseDouble(num);
if(two==0)
two=Double.parseDouble(Jtf.getText());

char c=operator.charAt(0);
switch(c)
{
case '+':one+=two;Jtf.setText(""+one);  num=Jtf.getText();bool=true;return;
case '-':one-=two;Jtf.setText(""+one); num=Jtf.getText();bool=true;return;
case '*':one*=two;Jtf.setText(""+one); num=Jtf.getText();bool=true;return;
case '/':one/=two;Jtf.setText(""+one); num=Jtf.getText();bool=true;return;
}
}
public static void main(String arg[]) 
{
  new counter(); 
}
}