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Код


import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

class Calculator extends JFrame {
   public Calculator() {
       setTitle("Calculator");
       getContentPane().add(new CalculatorPanel());
   }

   public static void main(String[] args) {
       Calculator frame = new Calculator();
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       frame.setBounds(500,500,250,200);
       frame.show();
   }
}

class CalculatorPanel extends JPanel {

   private JLabel display;
   private JPanel panel;
   private double result;
   private String lastCommand;
   private boolean start;

   public CalculatorPanel() {
       setLayout(new BorderLayout());

       result = 0;
       lastCommand = "=";
       start = true;
       display = new JLabel("0");

       add(display, BorderLayout.NORTH);

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

       panel = new JPanel();
       panel.setLayout(new GridLayout(5, 4));

       addButton("sin", command);
       addButton("cos", command);
       addButton("tan", command);
       addButton("sqrt", command);
       

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

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

       addButton("1", insert);
       addButton("2", insert);
       addButton("3", insert);
       addButton("-", command);

       addButton("0", insert);
       addButton(".", insert);
       addButton("=", command);
       addButton("+", command);


       
        

       add(panel, BorderLayout.SOUTH);
   }

   private void addButton(String label, ActionListener listener) {
       JButton button = new JButton(label);
       button.addActionListener(listener);
       panel.add(button);
   }

   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);
       }
   }

   private class CommandAction implements ActionListener {
       public void actionPerformed(ActionEvent evt) {
           String command = evt.getActionCommand();

           if (start) {
               if (command.equals("-")) {
                   display.setText(command);
                   start = false;
               } else
                   lastCommand = command;
           } else {
               calculate(Double.parseDouble(display.getText()));
               lastCommand = command;
               start = true;
           }
       }
   }

   public void calculate(double x) {    
   if (lastCommand.equals("+"))
           result += x;
       else if (lastCommand.equals("-"))
           result -= x;
       else if (lastCommand.equals("*"))
           result *= x;
       else if (lastCommand.equals("/"))
           result /= x;

else if (lastCommand.equals("sin"))
              result = Math.sin(x);
          

else if (lastCommand.equals("cos"))
           result = Math.cos(x);
       

else if (lastCommand.equals("tan"))
           result = Math.tan(x);
else if (lastCommand.equals("sqrt"))
           result = Math.sqrt(x);


       else if (lastCommand.equals("=")) result=x;
       display.setText("" + result);
   }
}

Цитата(f999t1 @ 16.5.2006, 21:49

)

Но при вводе числа он вычесляет,только при повторной попытке.

Код


private class CommandAction implements ActionListener {
       public void actionPerformed(ActionEvent evt) {
           String command = evt.getActionCommand();
           if (start) {
               if (command.equals("-")) {
                   display.setText(command);
                   start = false;
               } else
                   lastCommand = command;
           } else {
// Это код будет изменен ------------------------------------------
               calculate(Double.parseDouble(display.getText()));
               lastCommand = command;
//--------------------------------------------------------------------------
               start = true;
           }
       }
   }

Код


private class CommandAction implements ActionListener {
       public void actionPerformed(ActionEvent evt) {
           String command = evt.getActionCommand();
           if (start) {
               if (command.equals("-")) {
                   display.setText(command);
                   start = false;
               } else
                   lastCommand = command;
           } else {
// Это код был изменен ------------------------------------------
               lastCommand = command;  
               calculate(Double.parseDouble(display.getText()));
//--------------------------------------------------------------------------
               start = true;
           }
       }
   }

Код


private class CommandAction implements ActionListener {
        public void actionPerformed(ActionEvent evt) {
            String command = evt.getActionCommand();
            if (start) {
                if (command.equals("-")) {
                    display.setText(command);
                    start = false;
                } else {
                    lastCommand = command;
                }
            } else {
                if (command.equals("sin") || command.equals("cos") || command.equals("tan") || command.equals("sqrt")) {
                    lastCommand = command;
                    calculate(Double.parseDouble(display.getText()));
                    lastCommand = "=";
                }
                else {
                     calculate(Double.parseDouble(display.getText()));
                     lastCommand = command;
                }
               
                start = true;
            }
        }
    }

Цитата(f999t1 @ 16.5.2006, 23:33

)

а как сделать, что бы она вычисляла sin результата,