Java program for creating Basic Calculator

/* Basic Calculator */

import java.awt.*;
import java.awt.event.*;

class MyCalculator extends Frame implements ActionListener
{
 double x=0.0,y=0.0,z=0.0;
 int op=0;
 
 Panel p1,p2;
 Label lblR;
 Button btn1,btn2,btn3,btnA,btn4,btn5,btn6,btnS,btn7,btn8,btn9,btnM,btn0,btnC,btnE,btnD;
 public MyCalculator()
 {
  super("My Calculator");
  addWindowListener(new WindowAdapter()
       {
        public void windowClosing(WindowEvent we)
        {
         System.exit(0);
        } 
       }
      );
  setSize(300,200);
  setResizable(false);
  
  p1=new Panel();
  p2=new Panel();
  
  lblR=new Label("0");
  
  btn1=new Button("1");
  btn2=new Button("2");
  btn3=new Button("3");
  btnA=new Button("+");
  
  btn4=new Button("4");
  btn5=new Button("5");
  btn6=new Button("6");
  btnS=new Button("-");
  
  btn7=new Button("7");
  btn8=new Button("8");
  btn9=new Button("9");
  btnM=new Button("*");
  
  btn0=new Button("0");
  btnC=new Button("C");
  btnE=new Button("=");
  btnD=new Button("/");
  
  lblR.setFont(new Font("Arial",Font.BOLD,20));
  btn1.setFont(new Font("Arial",Font.BOLD,20));
  btn2.setFont(new Font("Arial",Font.BOLD,20));
  btn3.setFont(new Font("Arial",Font.BOLD,20));
  btnA.setFont(new Font("Arial",Font.BOLD,20));
  btn4.setFont(new Font("Arial",Font.BOLD,20));
  btn5.setFont(new Font("Arial",Font.BOLD,20));
  btn6.setFont(new Font("Arial",Font.BOLD,20));
  btnS.setFont(new Font("Arial",Font.BOLD,20));
  btn7.setFont(new Font("Arial",Font.BOLD,20));
  btn8.setFont(new Font("Arial",Font.BOLD,20));
  btn9.setFont(new Font("Arial",Font.BOLD,20));
  btnM.setFont(new Font("Arial",Font.BOLD,20));
  btn0.setFont(new Font("Arial",Font.BOLD,20));
  btnC.setFont(new Font("Arial",Font.BOLD,20));
  btnE.setFont(new Font("Arial",Font.BOLD,20));
  btnD.setFont(new Font("Arial",Font.BOLD,20));
  
  p1.setLayout(new BorderLayout());
  p1.add(lblR,BorderLayout.NORTH);
  
  p2.setLayout(new GridLayout(4,4));
  p2.add(btn1);
  p2.add(btn2);
  p2.add(btn3);
  p2.add(btnA);
  p2.add(btn4);
  p2.add(btn5);
  p2.add(btn6);
  p2.add(btnS);
  p2.add(btn7);
  p2.add(btn8);
  p2.add(btn9);
  p2.add(btnM);
  p2.add(btn0);
  p2.add(btnC);
  p2.add(btnE);
  p2.add(btnD);
  
  setLayout(new BorderLayout());
  add(p1,BorderLayout.NORTH);
  add(p2,BorderLayout.CENTER);
  
  btn1.addActionListener(this);
  btn2.addActionListener(this);
  btn3.addActionListener(this);
  btnA.addActionListener(this);
  btn4.addActionListener(this);
  btn5.addActionListener(this);
  btn6.addActionListener(this);
  btnS.addActionListener(this);
  btn7.addActionListener(this);
  btn8.addActionListener(this);
  btn9.addActionListener(this);
  btnM.addActionListener(this);
  btn0.addActionListener(this);
  btnC.addActionListener(this);
  btnE.addActionListener(this);
  btnD.addActionListener(this);
  
  setVisible(true);
 }
 
 public void actionPerformed(ActionEvent ae)
 {
  if(ae.getSource()==btn1)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+1;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btn2)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+2;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btn3)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+3;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btn4)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+4;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btn5)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+5;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btn6)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+6;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btn7)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+7;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btn8)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+8;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btn9)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+9;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btn0)
  {
   x=Double.valueOf(lblR.getText());
   x=x*10+0;
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btnC)
  {
   x=Double.valueOf(lblR.getText());
   x=Math.floor(x/10);
   lblR.setText(String.valueOf(x));
  } 
  
  if(ae.getSource()==btnA)
  {
   y=x;
   x=0.0;
   lblR.setText(String.valueOf(x));
   op=1;
  } 
  
  if(ae.getSource()==btnS)
  {
   y=x;
   x=0.0;
   lblR.setText(String.valueOf(x));
   op=2;
  } 
  
  if(ae.getSource()==btnM)
  {
   y=x;
   x=0.0;
   lblR.setText(String.valueOf(x));
   op=3;
  } 
  
  if(ae.getSource()==btnD)
  {
   y=x;
   x=0.0;
   lblR.setText(String.valueOf(x));
   op=4;
  } 
  
  if(ae.getSource()==btnE)
  {
   if(op==1)
   {
    z=y+x;
    lblR.setText(String.valueOf(z));
    x=z;
   }
   
   if(op==2)
   {
    z=y-x;
    lblR.setText(String.valueOf(z));
    x=z;
   }
   
   if(op==3)
   {
    z=y*x;
    lblR.setText(String.valueOf(z));
    x=z;
   }
   
   if(op==4)
   {
    if(x!=0)
    {
     z=y/x;
     lblR.setText(String.valueOf(z));
     x=z;  
    }
    
   }
   
  } 
  
 }
 
 public static void main(String[] args)
 {
  new MyCalculator();
 }
}