calc1

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.Vector;

public class CalculatorLab extends JFrame implements ActionListener
{
	private JPanel keypad;
	private JPanel inputs;
	private JTextField firstInput = new JTextField(25);
	private JTextField secondInput = new JTextField(25);
	private JTextField results = new JTextField(25);
	private JLabel operatorLbl = new JLabel("+");
	private JLabel equalsLbl = new JLabel("=");
	private String operator;
	private boolean first = true;
	private boolean second = false;

	public static void main(String[] args)
	{
		CalculatorLab frame = new CalculatorLab();
		frame.setSize(500,300);
		frame.setVisible(true);
	}

	public CalculatorLab()
	{
		super( "My Calculator" );
		init();
	}

	private void init()
	{
		setLayout( new BorderLayout() );
		keypad = new JPanel(new GridLayout(6,3));
		String[] labels = {"0","1","2","3","4","5","6","7","8","9","+","-","*","/","="," ","Clear"," "};
		for (int i = 0; i < labels.length; i++)
		{
			keypad.add(createButton(labels[i]));
		}
		add("East", keypad);

		JButton clear = new JButton("Clear");

		inputs = new JPanel(new GridLayout(4,2));
		inputs.add(new JLabel("Enter First Input:"));
		inputs.add(firstInput);
		operatorLbl.setHorizontalAlignment(SwingConstants.RIGHT);
		inputs.add(operatorLbl);
		inputs.add(new JLabel(""));
		inputs.add(new JLabel("Enter Second Input:"));
		inputs.add(secondInput);
		equalsLbl.setHorizontalAlignment(SwingConstants.RIGHT);
		inputs.add(equalsLbl);
		inputs.add(results);
		add("Center", inputs);

		clear.addActionListener(this);

	}
	private JButton createButton( String name )
	{
		JButton b = new JButton( name );
		b.addActionListener( this );
		return b;

	}
	public void actionPerformed( ActionEvent e )
	{
		String cmd = e.getActionCommand();
		if (cmd.equals("+")||cmd.equals("-")||cmd.equals("*")||cmd.equals("/"))
		{
			firstInput.setBackground(null);
			secondInput.setBackground(Color.YELLOW);
			operator = cmd;
			operatorLbl.setText(cmd);
			first = false;
			second = true;
		}
		else if (first)
		{
			firstInput.setBackground(Color.YELLOW);
			firstInput.setText(firstInput.getText()+cmd);
			results.setText("");
		}
		else if (cmd.equals("="))
		{
			secondInput.setBackground(null);
			results.setBackground(Color.YELLOW);
			second = false;
			results.setText(calculateResults());
			resetCalc();
		}
		else if (second)
		{
			secondInput.setText(secondInput.getText()+cmd);
		}
		else if (clear)

	}
	public String calculateResults()
	{
		double resultsValue = 0;
		if (operator.equals("+"))
		{
			resultsValue = Double.parseDouble(firstInput.getText()) + Double.parseDouble(secondInput.getText());
		}
		else if (operator.equals("-"))
		{
			resultsValue = Double.parseDouble(firstInput.getText()) - Double.parseDouble(secondInput.getText());
		}
		else if (operator.equals("*"))
		{
			resultsValue = Double.parseDouble(firstInput.getText()) * Double.parseDouble(secondInput.getText());
		}
		else if (operator.equals("/"))
		{
			resultsValue = Double.parseDouble(firstInput.getText()) / Double.parseDouble(secondInput.getText());
		}

		return Double.toString(resultsValue);
	}
	public void resetCalc()
	{
		firstInput.setText("");
		secondInput.setText("");
		first = true;
		second = false;
	}
}