calculator program using Java Programming

 Java calculator can be easily created by creating buttons and texbox. For handling event we implement ActionListener event listener interface.

import java.awt.*;
import java.awt.event.*;
public class calculator extends Frame implements ActionListener
{
String s;
int n=0,val,sum,dif,mult,divs;
int op;
TextField tf;
Button b1,b2,b3,b4,b5,b6,b7,b8,b9,b0,plus,sub,mul,div,eq,cc;
public calculator()
{
super("Calculator");
Panel pn1=new Panel();
Panel pn2=new Panel();
pn2.setLayout(new FlowLayout(FlowLayout.CENTER));
tf=new TextField(10);
pn2.add(tf);
pn1.add(pn2);
Panel pn3=new Panel();
pn3.setLayout(new GridLayout(4,4));
b1=new Button("1");
b2=new Button("2");
b3=new Button("3");
b4=new Button("4");
b5=new Button("5");
b6=new Button("6");
b7=new Button("7");
b8=new Button("8");
b9=new Button("9");
b0=new Button("0");
plus=new Button("+");
sub=new Button("-");
mul=new Button("*");
div=new Button("/");
eq=new Button("=");
cc=new Button("C");
pn3.add(b7);
pn3.add(b8);
pn3.add(b9);
pn3.add(div);
pn3.add(b4);
pn3.add(b5);
pn3.add(b6);
pn3.add(mul);
pn3.add(b1);
pn3.add(b2);
pn3.add(b3);
pn3.add(sub);
pn3.add(b0);
pn3.add(cc);
pn3.add(eq);
pn3.add(plus);
pn1.add(pn3);
add(pn1);
b1.addActionListener(this);
b2.addActionListener(this);
b3.addActionListener(this);
b4.addActionListener(this);
b5.addActionListener(this);
b6.addActionListener(this);
b7.addActionListener(this);
b8.addActionListener(this);
b9.addActionListener(this);
b0.addActionListener(this);
cc.addActionListener(this);
plus.addActionListener(this);
sub.addActionListener(this);
mul.addActionListener(this);
div.addActionListener(this);
eq.addActionListener(this);
addWindowListener(new winadp());
}
public class winadp extends WindowAdapter
{
public void windowClosing(WindowEvent we)
{
System.exit(0);
}
}
public void actionPerformed(ActionEvent ae)
{
if(ae.getSource()==b1)
tf.setText(tf.getText()+"1");
if(ae.getSource()==b2)
tf.setText(tf.getText()+"2");
if(ae.getSource()==b3)
tf.setText(tf.getText()+"3");
if(ae.getSource()==b4) 
tf.setText(tf.getText()+"4");
if(ae.getSource()==b5)
tf.setText(tf.getText()+"5");
if(ae.getSource()==b6)
tf.setText(tf.getText()+"6");
if(ae.getSource()==b7)
tf.setText(tf.getText()+"7");
if(ae.getSource()==b8)
tf.setText(tf.getText()+"8");
if(ae.getSource()==b9)
tf.setText(tf.getText()+"9");
if(ae.getSource()==b0)
tf.setText(tf.getText()+"0");
if(ae.getSource()==cc)
tf.setText(null);
if(ae.getSource()==plus)
{
s=plus.getLabel();
n=Integer.parseInt(tf.getText());
tf.setText("");
}
if(ae.getSource()==sub)
{
s=sub.getLabel();
n=Integer.parseInt(tf.getText());
tf.setText("");
}
if(ae.getSource()==mul)
{
s=mul.getLabel();
n=Integer.parseInt(tf.getText());
tf.setText("");
}
if(ae.getSource()==div)
{
s=div.getLabel();
n=Integer.parseInt(tf.getText());
tf.setText("");
}
if(ae.getSource()==eq)
{
val=Integer.parseInt(tf.getText());
if(s.equals("+"))
{
sum=n+val;
tf.setText(String.valueOf(sum));
}
if(s.equals("-"))
{
dif=n-val;
tf.setText(String.valueOf(dif));
}
if(s.equals("*"))
{
mult=n*val;
tf.setText(String.valueOf(mult));
}
if(s.equals("/"))
{
divs=n/val;
tf.setText(String.valueOf(divs));
}
}
}
public static void main(String args[])
{
calculator cal=new calculator();
cal.setSize(200,250);
cal.setVisible(true);
}
}

 

 

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