Calculator Design

import java.util.Random;

import java.applet.Applet;

import java.awt.Graphics;

import java.awt.Button;

import java.awt.GridLayout;

import java.awt.Panel;

import java.awt.TextField;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.event.ActionListener;

import java.awt.event.ActionEvent;

/*

<applet code=MyApplet width = 400 height= 200>

</applet>

*/

public class MyApplet extends Applet implements ActionListener,Runnable {

    Random rand;

    Button bt[];

    Panel pnl1;

    TextField ipTextField;

    String fnum,snum;

    boolean aflag,sflag,mflag,dflag,dotflag,sinflag,cosflag,tanflag;

    public void run(){

    }

    public void init(){

        setBackground(Color.white);

        rand = new Random();

        fnum = "0";

        snum = "0";

        int nb=25;

        bt = new Button[28];

        pnl1 = new Panel();

        ipTextField = new TextField(10);

        setLayout(new BorderLayout());

        pnl1.setLayout(new GridLayout(7,4));

        for(int i=0;i<=9;i++)

            bt[i] = new Button( new Integer(i).toString());

        bt[10] = new Button("+");

        bt[11] = new Button("-");

        bt[12] = new Button("X");

        bt[13] = new Button("/");

        bt[14] = new Button("=");

        bt[15] = new Button(".");

        bt[16] = new Button("AC");

        bt[17] = new Button("sin");

        bt[18] = new Button("cos");

        bt[19] = new Button("tan");

        bt[20] = new Button("Rand");

        bt[21] = new Button("Backspace");

        bt[22] = new Button("Sqrt");

        bt[23] = new Button("X^2");

        bt[24] = new Button("X!");

        bt[25] = new Button("1/X");

        bt[26] = new Button("PI");

        bt[27] = new Button("X^3");

        for(int i=0;i<28;i++) {

            pnl1.add(bt[i]);

            bt[i].addActionListener(this);

            }

        add(ipTextField,BorderLayout.NORTH);

        add(pnl1,BorderLayout.CENTER);

}

public void actionPerformed(ActionEvent ae) {

    String msg;

    msg = ae.getActionCommand();

    String tmsg = ipTextField.getText();

    if(msg.equals("0"))

        tmsg = tmsg + "0";

    else if(msg.equals("1"))

        tmsg = tmsg + "1";

    else if(msg.equals("2"))

        tmsg = tmsg + "2";

    else if(msg.equals("3"))

        tmsg = tmsg + "3";

    else if(msg.equals("4"))

        tmsg = tmsg + "4";

    else if(msg.equals("5"))

        tmsg = tmsg + "5";

    else if(msg.equals("6"))

        tmsg = tmsg + "6";

    else if(msg.equals("7"))

        tmsg = tmsg + "7";

    else if(msg.equals("8"))

        tmsg = tmsg + "8";

    else if(msg.equals("9"))

         tmsg = tmsg + "9";

    else if(msg.equals("AC")) { // All clear button.............

         fnum = "";

         snum = "";

         tmsg = "";

         aflag = false;

         sflag = false;

         mflag = false;

         dflag = false;

         dotflag = false;

    }

    else if(msg.equals("Backspace")) {

        fnum = ipTextField.getText();

        if(fnum == null)

            tmsg = "";

        else

            tmsg = fnum.substring(0,fnum.length()-1);

    }

    else if(msg.equals("+")) {

        fnum = ipTextField.getText();

        tmsg = "";

        aflag = true;

        dotflag = false;

    }

    else if(msg.equals("-")) {

        fnum = ipTextField.getText();

        tmsg = "";

        sflag = true;

        dotflag = false;

    }

    else if(msg.equals("X"))

{

fnum = ipTextField.getText();

tmsg = "";

mflag = true;

dotflag = false;

}

else if(msg.equals("/"))

{

fnum = ipTextField.getText();

tmsg = "";

dflag = true;

dotflag = false;

}

else if(msg.equals("sin"))

{

fnum = ipTextField.getText();

if(fnum==null) fnum = "0.0";

tmsg = "";

dotflag = false;

Double dobj;

double dval;

dobj = Double.valueOf(fnum);

dval = dobj.doubleValue();

tmsg = Math.sin(dval)+"";

}

else if(msg.equals("cos"))

{

fnum = ipTextField.getText();

if(fnum==null) fnum = "0.0";

tmsg = "";

dotflag = false;

Double dobj;

double dval;

dobj = Double.valueOf(fnum);

dval = dobj.doubleValue();

tmsg = Math.cos(dval)+"";

}

else if(msg.equals("tan"))

{

fnum = ipTextField.getText();

if(fnum==null) fnum = "0.0";

tmsg = "";

dotflag = false;

Double dobj;

double dval;

dobj = Double.valueOf(fnum);

dval = dobj.doubleValue();

tmsg = Math.tan(dval)+"";

}

else if(msg.equals("X^2"))

{

fnum = ipTextField.getText();

if(fnum==null) fnum = "0.0";

tmsg = "";

dotflag = false;

Double dobj;

double dval;

dobj = Double.valueOf(fnum);

dval = dobj.doubleValue();

tmsg = (dval*dval)+"";

}

else if(msg.equals("X^3"))

{

fnum = ipTextField.getText();

if(fnum==null) fnum = "0.0";

tmsg = "";

dotflag = false;

Double dobj;

double dval;

dobj = Double.valueOf(fnum);

dval = dobj.doubleValue();

tmsg = (dval*dval*dval)+"";

}

else if(msg.equals("Sqrt"))

{

fnum = ipTextField.getText();

if(fnum==null) fnum = "0.0";

tmsg = "";

dotflag = false;

Double dobj;

double dval;

dobj = Double.valueOf(fnum);

dval = dobj.doubleValue();

tmsg = Math.sqrt(dval)+"";

}

else if(msg.equals("X!"))

{

fnum = ipTextField.getText();

if(fnum==null) fnum = "0.0";

tmsg = "";

dotflag = false;

Double dobj;

double dval;

dobj = Double.valueOf(fnum);

dval = dobj.doubleValue();

long li=1;

for(int i = 1; i<=(int)dval;i++)

li *= i;

tmsg = li+"";

}

else if(msg.equals(".")&&(dotflag==false))

{

tmsg = tmsg + ".";

dotflag = true;

}

else if(msg.equals("PI"))

{

tmsg = Math.PI+"";

dotflag = true;

}

else if(msg.equals("Rand"))

{

tmsg = rand.nextFloat()+"";

dotflag = true;

}

else if(msg.equals("1/X"))

{

fnum = ipTextField.getText();

double d1;

Double do1;

do1 = Double.valueOf(fnum);

d1 = do1.doubleValue();

if(d1==0.0)

{

try

{

ipTextField.setText("Divide by Zero Attempted.");

Thread.sleep(1000);

}

catch(InterruptedException ie)

{

}

tmsg = "";

}

else

{

tmsg =( (1/d1) + "" );

dotflag = true;

}

}

else if(msg.equals("="))

{

snum = ipTextField.getText();

if(snum == null) snum = "0";

if(fnum == null) fnum = "0";

double n1,n2;

Double do1,do2;

do1 = Double.valueOf(fnum);

do2 = Double.valueOf(snum);

n1 = do1.doubleValue();

n2 = do2.doubleValue();

if(aflag==true)

{

tmsg = (n1+n2+"");

}

if(sflag==true)

{

tmsg = (n1-n2+"");

}

if(mflag==true)

{

tmsg = (n1*n2+"");

}

if(dflag==true)

{

tmsg = (n1/n2+"");

}

aflag = false;

sflag = false;

mflag = false;

dflag = false;

dotflag = true;

}

ipTextField.setText(tmsg);

}

public void paint(Graphics g)

{

}

}