//package v1ch09.Calculator;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.ArrayList;
/*import java.util.Arrays;
import java.util.Collection;
import java.util.Scanner;*/


/**
 * @version 1.33 2007-06-12
 * @author Cay Horstmann
 */
public class Calculator
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(new Runnable()
         {
            public void run()
            {
               CalculatorFrame frame = new CalculatorFrame();
               frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
               frame.setVisible(true);
            }
         });
   }
}

/**
 * A frame with a calculator panel.
 */
class CalculatorFrame extends JFrame
{
   public CalculatorFrame()
   {
      setTitle("Calculator");
      CalculatorPanel panel = new CalculatorPanel();
      add(panel);
      pack();
   }
}

/**
 * A panel with calculator buttons and a result display.
 */
class CalculatorPanel extends JPanel
{
   public CalculatorPanel()
   {
      setLayout(new BorderLayout());

      result = 0;
      lastCommand = "=";
      start = true;

      // add the display

      display = new JButton("0");
      display.setEnabled(false);
      add(display, BorderLayout.NORTH);

      ActionListener insert = new InsertAction();
      ActionListener command = new CommandAction();

      // add the buttons in a 4 x 4 grid

      panel = new JPanel();
      panel.setLayout(new GridLayout(4, 4));

      addButton("7", insert);
      addButton("8", insert);
      addButton("9", insert);
      addButton("/", command);

      addButton("*", command);
      addButton("4", insert);
      addButton("5", insert);
      addButton("6", insert);

      addButton("+", command);
      addButton("-", command);
      addButton("1", insert);
      addButton("2", insert);

      addButton("3", insert);
      addButton(".", insert);
      addButton("=", command);
      addButton("0", insert);
      addButton("MS", command);
      addButton("MR", command);


      add(panel, BorderLayout.CENTER);
   }

   /**
    * Adds a button to the center panel.
    * @param label the button label
    * @param listener the button listener
    */
   private void addButton(String label, ActionListener listener)
   {
      JButton button = new JButton(label);
      button.addActionListener(listener);
      panel.add(button);
   }

   /**
    * This action inserts the button action string to the end of the display text.
    */
   private class InsertAction implements ActionListener
   {
      public void actionPerformed(ActionEvent event)
      {
         String input = event.getActionCommand();
         if (start)
         {
            display.setText("");
            start = false;
         }
         display.setText(display.getText() + input);
      }
   }

   /**
    * This action executes the command that the button action string denotes.
    */
   public class CommandAction implements ActionListener
   {
      // int flag = 0;

      public void actionPerformed(ActionEvent event)
      {
         String command = event.getActionCommand();

         if (start)
         {
            //String command = event.getActionCommand();
            if (command.equals("-"))
            {
               display.setText(command);
               start = false;
            }
            else if (command.equals("MS"))
                {
                lastCommand = command;
                calculate(Double.parseDouble(display.getText()));

                }
            else lastCommand = command;
         }
         else
         {
            if (command.equals("MS"))
            {
            lastCommand = command;
            //calculate(Double.parseDouble(display.getText()));

            }
            calculate(Double.parseDouble(display.getText()));
            lastCommand = command;
            start = true;
         }
      }
   }

   /**
    * Carries out the pending calculation.
    * @param x the value to be accumulated with the prior result.
    */
   public void calculate(double x)
   {
      Stack_10080 obj = new Stack_10080();
      if (lastCommand.equals("+"))
          {
            result += x;
            display.setText("" + result);
          }
      else if (lastCommand.equals("-"))
          {
            result -= x;
            display.setText("" + result);
          }
      else if (lastCommand.equals("*"))
          {
            result *= x;
            display.setText("" + result);
          }
      else if (lastCommand.equals("/"))
          {
            result /= x;
            display.setText("" + result);
          }
      else if (lastCommand.equals("="))
          {
            result = x;
            display.setText("" + result);
          }
      else if (lastCommand.equals("MS"))
          {
            obj.push(x);
            lastCommand = "=";
            result=x;
            //lastCommand = "=";
            //result = 0;
            //display.setText("" + "0.0");
          }
      else if (lastCommand.equals("MR"))
          {
          Double temp = obj.pop();
          result = temp;
          }

      //display.setText("" + result);
   }

   private JButton display;
   private JPanel panel;
   private double result;
   private String lastCommand;
   private boolean start;
}


class Stack_10080 {

    ArrayList<Double>str = new ArrayList<Double>(1);
    public void push(Double str2)
    {
            str.add(str2);
            System.out.println(str2);
            /*for(int i=0;i<str.size();i++)
            {
                System.out.println(str.get(i));
            }*/

    }
    public Double pop()
    {
        Double temp1,temp3=0.0;
        if(str.size()==0)
        {
            return temp3;
        }
        temp1 = str.get(str.size()-1);
        str.remove(str.size()-1);
        System.out.println(temp1);
        return temp1;
    }
}