/* Coded By Karthik Ananthapadmanaban 
   Web - http://www.utdallas.edu/~kxa060100
*/

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

public class Calculator extends Frame implements ActionListener, ItemListener, WindowListener
{
	TextField txtMain;
	Button add, sub, mul, div, eq, in, clear;
	String curr;
	public int cmdprev;
	double num1,num2;
	boolean flag,append=true;

	Button btn[]=new Button[11];

	Checkbox conv;
	Button sin, cos, tan;
	
	double ctext;

	Button exp, log, pow, sqr;

	public Calculator()
	{
		super("Calculator");
		setSize(350,250);
		addWindowListener(this);
		
		Panel ib = new Panel();
		
		txtMain=new TextField(20);
	        txtMain.setEditable(false);
		ib.add(txtMain);

		add(ib,BorderLayout.NORTH);

		txtMain.setText("0");

		Panel tb = new Panel();

		add=new Button("+");
		add.addActionListener(this);
		tb.add(add);

		sub=new Button("-");
		sub.addActionListener(this);
		tb.add(sub);

		mul=new Button("*");
		mul.addActionListener(this);
		tb.add(mul);
		
		div=new Button("/");
		div.addActionListener(this);
		tb.add(div);

		in=new Button("1/x");
		in.addActionListener(this);
		tb.add(in);

		eq=new Button("=");
		eq.addActionListener(this);
		tb.add(eq);

		clear=new Button("C");
		clear.addActionListener(this);
		tb.add(clear);

		for (int i=0; i<10; i++)
		{
			btn[i]=new Button(Integer.toString(i));
			btn[i].addActionListener(this);
			tb.add(btn[i]);
		}

		btn[10]=new Button(".");
		btn[10].addActionListener(this);
		tb.add(btn[10]);

		add(tb,BorderLayout.CENTER);

		tb.setLayout(new GridLayout(3,6,5,5));

		Panel cb = new Panel();

		conv=new Checkbox("Inv");
		conv.addItemListener(this);
		cb.add(conv);

		sin=new Button("Sin");
		sin.addActionListener(this);
		cb.add(sin);

		cos=new Button("Cos");
		cos.addActionListener(this);
		cb.add(cos);

		tan=new Button("Tan");
		tan.addActionListener(this);
		cb.add(tan);

		add(cb,BorderLayout.EAST);

		cb.setLayout(new GridLayout(4,1,5,5));

		Panel eb = new Panel();

		exp=new Button("Exp");
		exp.addActionListener(this);
		eb.add(exp);

		log=new Button("Log");
		log.addActionListener(this);
		eb.add(log);

		pow=new Button("Pow");
		pow.addActionListener(this);
		eb.add(pow);

		sqr=new Button("Sqrt");
		sqr.addActionListener(this);
		eb.add(sqr);

		add(eb,BorderLayout.SOUTH);
	}
	
    public void windowClosing(WindowEvent event) {   	
    	setVisible(false);
    	System.exit(0);
        }

    public void windowDeiconified(WindowEvent event) {
    }
    public void windowIconified(WindowEvent event) {
    }
    public void windowActivated(WindowEvent event) {
    }
    public void windowDeactivated(WindowEvent event) {
    }
    public void windowOpened(WindowEvent event) {
    }
    public void windowClosed(WindowEvent event) {
    }

	public void actionPerformed(ActionEvent ae)
	{
		String cmd=ae.getActionCommand();
		
		if (cmd.equals("+"))
		{
			cmdprev=1;
			if (flag)
			{
				curr=txtMain.getText();
				try
				{
					num2=Double.parseDouble(curr);
					num1=num1 + num2;
					txtMain.setText(Double.toString(num1));
				}
				catch (NumberFormatException e)
				{
					txtMain.setText("Invalid Number");
				}			
			}
			else
			{
				flag=true;
				append=false;
				curr=txtMain.getText();
				num1=Double.parseDouble(curr);
			}
		}
		else if (cmd.equals("-"))
		{
			cmdprev=2;
			if (flag)
			{
				curr=txtMain.getText();
				try
				{
					num2=Double.parseDouble(curr);
					num1=num1 - num2;
					txtMain.setText(Double.toString(num1));
				}
				catch (NumberFormatException e)
				{
					txtMain.setText("Invalid Number");
				}			
			}
			else
			{
				flag=true;
				append=false;
				curr=txtMain.getText();
				num1=Double.parseDouble(curr);
			}
		}
		else if (cmd.equals("*"))
		{
			cmdprev=3;
			if (flag)
			{
				curr=txtMain.getText();
				try
				{
					num2=Double.parseDouble(curr);
					num1=num1 * num2;
					txtMain.setText(Double.toString(num1));
				}
				catch (NumberFormatException e)
				{
					txtMain.setText("Invalid Number");
				}			
			}
			else
			{
				flag=true;
				append=false;
				curr=txtMain.getText();
				num1=Double.parseDouble(curr);
			}
		}
		else if (cmd.equals("/"))
		{
			cmdprev=4;
			if (flag)
			{
				curr=txtMain.getText();
				try
				{
					num2=Double.parseDouble(curr);
					try
					{
					num1=num1 / num2;						
					txtMain.setText(Double.toString(num1));
					}
					catch (ArithmeticException e)
					{
						txtMain.setText("Divide by 0");
					}
				}
				catch (NumberFormatException e)
				{
					txtMain.setText("Invalid Number");
				}			
			}
			else
			{
				flag=true;
				append=false;
				curr=txtMain.getText();
				num1=Double.parseDouble(curr);
			}
		}
		else if (cmd.equals("="))
		{
			try
			{
				num2=Double.parseDouble(txtMain.getText());
				switch(cmdprev)
				{
					case 1: num1 = num1 + num2;
							txtMain.setText(Double.toString(num1));
							break;
					case 2: num1 = num1 - num2;
							txtMain.setText(Double.toString(num1));
							break;
					case 3: num1 = num1 * num2;
							txtMain.setText(Double.toString(num1));
							break;
					case 4: try
							{
								num1 = num1 / num2;
								txtMain.setText(Double.toString(num1));
							}
							catch (ArithmeticException e)
							{
								txtMain.setText("Divide by 0");
							}
							break;					        
				}
			}
			catch (NumberFormatException e)
			{
				txtMain.setText("Invalid number");
			}
		}
		else if (cmd.equals("C"))
		{
			flag=false;
			txtMain.setText("0");
		}
		else if (cmd.equals("0"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("0");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "0");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("0");
					append=true;
				}
			}
		}
		else if (cmd.equals("1"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("1");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "1");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("1");
					append=true;
				}
			}
		}
		else if (cmd.equals("2"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("2");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "2");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("2");
					append=true;
				}
			}
		}
		else if (cmd.equals("3"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("3");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "3");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("3");
					append=true;
				}
			}
		}
		else if (cmd.equals("4"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("4");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "4");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("4");
					append=true;
				}
			}
		}
		else if (cmd.equals("5"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("5");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "5");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("5");
					append=true;
				}
			}
		}
		else if (cmd.equals("6"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("6");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "6");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("6");
					append=true;
				}
			}
		}
		else if (cmd.equals("7"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("7");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "7");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("7");
					append=true;
				}
			}
		}
		else if (cmd.equals("8"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("8");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "8");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("8");
					append=true;
				}
			}
		}
		else if (cmd.equals("9"))
		{
			if (txtMain.getText().equals("0"))
			{
				txtMain.setText("9");
			}
			else
			{
				if (append)
				{
					txtMain.setText(txtMain.getText() + "9");
				}
				else
				{
					txtMain.setText("");
					txtMain.setText("9");
					append=true;
				}
			}
		}
		else if (cmd.equals("."))
		{
			if (txtMain.getText().equals(""))
			{
				txtMain.setText("0.");
			}
			else
			{
				txtMain.setText(txtMain.getText() + ".");
			}
		}
		else if (cmd.equals("Sin"))
		{
			try
			{
				ctext=Double.parseDouble(txtMain.getText());
				if (conv.getState())
				{
					double r=Math.asin((double) ctext);
					txtMain.setText(Double.toString(r));
				}
				else
				{
					double r=Math.sin((double) ctext);
					txtMain.setText(Double.toString(r));
				}
			}
			catch (NumberFormatException e)
			{
				txtMain.setText("Invalid Number");
			}
		}
		else if (cmd.equals("Cos"))
		{
			try
			{
				ctext=Double.parseDouble(txtMain.getText());
				if (conv.getState())
				{
					double r=Math.acos((double) ctext);
					txtMain.setText(Double.toString(r));
				}
				else
				{
					double r=Math.cos((double) ctext);
					txtMain.setText(Double.toString(r));
				}
			}
			catch (NumberFormatException e)
			{
				txtMain.setText("Invalid Number");
			}
		}
		else if (cmd.equals("Tan"))
		{
			try
			{
				ctext=Double.parseDouble(txtMain.getText());
				if (conv.getState())
				{
					double r=Math.atan((double) ctext);
					txtMain.setText(Double.toString(r));
				}
				else
				{
					double r=Math.tan((double) ctext);
					txtMain.setText(Double.toString(r));
				}
			}
			catch (NumberFormatException e)
			{
				txtMain.setText("Invalid Number");
			}
		}
		repaint();
	}

	public void itemStateChanged(ItemEvent ae)
	{
		repaint();
	}

	public static void main(String args[])
	{
		Calculator calc=new Calculator();
		calc.setVisible(true);
	}
}