Write a java program to implement a simple arithmetic calculator. Perform appropriate validations.

 

Write a java program to implement a simple arithmetic calculator. Perform appropriate validations.

calr.java 

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

class Calr extends JFrame implements ActionListener

{

static double a=0,b=0,result=0;

static int operator=0;

JTextField t1;

JPanel p1,p2;// p1=textbox,button

JButton b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12,b13,b14,b15,bclr;

Calr()

{

t1=new JTextField(17);

p1=new JPanel();

p2=new JPanel();

p2.setLayout(new GridLayout(4,4));

b0=new JButton("1");

b1=new JButton("2");

b2=new JButton("3");

b3=new JButton("+");

b4=new JButton("4");

b5=new JButton("5");

b6=new JButton("6");

b7=new JButton("-");

b8=new JButton("7");

b9=new JButton("8");

b10=new JButton("9");

b11=new JButton("*");

b12=new JButton("0");

b13=new JButton(".");

b14=new JButton("=");

b15=new JButton("/");

bclr=new JButton("Clear");

p2.add(b0);

b0.addActionListener(this);

p2.add(b1);

b1.addActionListener(this);

p2.add(b2);

b2.addActionListener(this);

p2.add(b3);

b3.addActionListener(this);

p2.add(b4);

b4.addActionListener(this);

p2.add(b5);

b5.addActionListener(this);

p2.add(b6);

b6.addActionListener(this);

p2.add(b7);

b7.addActionListener(this);

p2.add(b8);

b8.addActionListener(this);

p2.add(b9);

b9.addActionListener(this);

p2.add(b10);

b10.addActionListener(this);

p2.add(b11);

b11.addActionListener(this);

p2.add(b12);

b12.addActionListener(this);

p2.add(b13);

b13.addActionListener(this);

p2.add(b14);

b14.addActionListener(this);

p2.add(b15);

b15.addActionListener(this);

bclr.addActionListener(this);

setLayout(new BorderLayout());

p1.add(t1);p1.add(bclr);

add(p1,BorderLayout.NORTH);

add(p2);

setSize(300,400);

                setVisible(true);

                setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

public void actionPerformed(ActionEvent e)

{

if(e.getSource()==b0)

t1.setText(t1.getText().concat("1"));

if(e.getSource()==b1)

t1.setText(t1.getText().concat("2"));

if(e.getSource()==b2)

t1.setText(t1.getText().concat("3"));

if(e.getSource()==b4)

t1.setText(t1.getText().concat("4"));

if(e.getSource()==b5)

t1.setText(t1.getText().concat("5"));

if(e.getSource()==b6)

t1.setText(t1.getText().concat("6"));

if(e.getSource()==b8)

t1.setText(t1.getText().concat("7"));

if(e.getSource()==b9)

t1.setText(t1.getText().concat("8"));

if(e.getSource()==b10)

t1.setText(t1.getText().concat("9"));

if(e.getSource()==b12)

t1.setText(t1.getText().concat("0"));

if(e.getSource()==b13)

t1.setText(t1.getText().concat("."));

if(e.getSource()==b3)

{

a=Double.parseDouble(t1.getText());

operator=1;

t1.setText("");

} 

if(e.getSource()==b7)

{

a=Double.parseDouble(t1.getText());

operator=2;

t1.setText("");

}

if(e.getSource()==b11)

{

a=Double.parseDouble(t1.getText());

operator=3;

t1.setText("");

}

if(e.getSource()==b15)

{

a=Double.parseDouble(t1.getText());

operator=4;

t1.setText("");

}

if(e.getSource()==b14)

{

b=Double.parseDouble(t1.getText());

switch(operator)

{

case 1: result=a+b;

break;

case 2: result=a-b;

break;

case 3: result=a*b;

break;

case 4: result=a/b;

break;

default: result=0;

}

t1.setText(""+result);

}

if(e.getSource()==bclr)

t1.setText("");

}

public static void main(String arg[]) 

        {

            new Calr();     

        }

}