Simple Applet Calculator Program

import java.awt.*;

import java.awt.event.*;

import java.applet.*;

/*

<applet code=Calc width=300 height=200>

</applet>

*/

public class Calc extends Applet implements ActionListener

{

Button one=new Button("1");

Button two=new Button("2");

Button three=new Button("3");

Button four=new Button("4");

Button five=new Button("5");

Button six=new Button("6");

Button seven=new Button("7");

Button eight=new Button("8");

Button nine=new Button("9");

Button zero=new Button("0");

Button plus=new Button("+");

Button minus=new Button("-");

Button div=new Button("/");

Button mul=new Button("*");

Button eql=new Button("=");

Button bk=new Button("C");

Button point=new Button(".");

TextField dis=new TextField("0");

Label rs=new Label(" ",Label.RIGHT);

boolean flag=true,calc=true;

String sign="";

Double x=0.0,y=0.0;

public void init()

{

setLayout(new GridLayout(3,1));

Panel d=new Panel();

d.setBackground(Color.gray);

d.setForeground(Color.blue);

d.setLayout(new BorderLayout(2,2));

d.add(BorderLayout.CENTER,dis);

d.setFont(new Font("SansSerif",Font.BOLD,18));

Panel r=new Panel();

r.setBackground(Color.white);

r.setForeground(Color.black);

r.setLayout(new BorderLayout());

r.add(BorderLayout.WEST,rs);

Panel b=new Panel();

b.setFont(new Font("SansSerif",Font.BOLD,14));

b.setBackground(Color.gray);

b.setForeground(Color.red);

b.setLayout(new GridLayout(4,4));

b.add(one);

b.add(two);

b.add(three);

b.add(four);

b.add(five);

b.add(six);

b.add(seven);

b.add(eight);

b.add(nine);

b.add(zero);

b.add(plus);

b.add(minus);

b.add(div);

b.add(mul);

b.add(eql);

b.add(bk);

b.add(point);

add(d);

add(r);

add(b);

one.addActionListener(this);

two.addActionListener(this);

three.addActionListener(this);

four.addActionListener(this);

five.addActionListener(this);

six.addActionListener(this);

seven.addActionListener(this);

eight.addActionListener(this);

nine.addActionListener(this);

zero.addActionListener(this);

plus.addActionListener(this);

div.addActionListener(this);

minus.addActionListener(this);

mul.addActionListener(this);

eql.addActionListener(this);

bk.addActionListener(this);

point.addActionListener(this);

}

public void actionPerformed(ActionEvent a)

{

if(flag==true)

{

dis.setText("");

flag=false;

}

String i=dis.getText();

rs.setText("");

if(a.getSource()==one)

{

dis.setText(i+"1");

}

else if(a.getSource()==two)

{

dis.setText(i+"2");

}

else if(a.getSource()==three)

{

dis.setText(i+"3");

}

else if(a.getSource()==four)

{

dis.setText(i+"4");

}

else if(a.getSource()==five)

{

dis.setText(i+"5");

}

else if(a.getSource()==six)

{

dis.setText(i+"6");

}

else if(a.getSource()==seven)

{

dis.setText(i+"7");

}

else if(a.getSource()==eight)

{

dis.setText(i+"8");

}

else if(a.getSource()==nine)

{

dis.setText(i+"9");

}

else if(a.getSource()==zero)

{

dis.setText(i+"0");

}

else if(a.getSource()==point)

{

dis.setText(i+".");

}

if((a.getSource()==plus)||(a.getSource()==div)||(a.getSource()==mul)||(a.getSource()==minus))

{

dis.setText("");

sign=a.getActionCommand();

calc=false;

try

{

String temp0=i;

Double temp1=new Double(temp0);

x=temp1.doubleValue();

}

catch(NumberFormatException n)

{

rs.setText("Illigal data is enterd");

return;

}

flag=true;

i="";

}

if(a.getSource()==eql)

{

if(calc==true)

{

rs.setText("Please enter values");

}

if(!calc)

{

try

{

String temp2=i;

Double temp3=new Double(temp2);

y=temp3.doubleValue();

}

catch(NumberFormatException n)

{

rs.setText("Illigal data is enterd");

return;

}

}

dis.setText("");

if(sign.equals("+"))

dis.setText(x+" "+sign+" "+y+" = "+(x+y));

else if(sign.equals("-"))

dis.setText(x+" "+sign+" "+y+" = "+ (x-y));

else if(sign.equals("*"))

dis.setText(x+" "+sign+" "+y+" = "+ (x*y));

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

{

if(y!=0)

{

dis.setText(x+" "+sign+" "+y+" = "+ (x/y));

}

else

{

rs.setText("Division by zero is not possible");

}

}

}

if(a.getSource()==bk)

{

dis.setText("");

i="";

flag=true;

calc=true;

x=0.0;

y=0.0;

}

}

}