calculator project in java with source code.

 import java.awt.Color;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JTextField;

import javax.swing.UIManager;

import javax.swing.UnsupportedLookAndFeelException;

public class CalculatorApp extends JFrame implements ActionListener{

 

private static final long serialVersionUID = -1315467733997126666L;

static JFrame frame;

static JTextField textField;

String first, second, operator;

CalculatorApp() {

first = second = operator = "";

}

@SuppressWarnings("deprecation")

public static void main(String[] args) throws UnsupportedLookAndFeelException {

frame = new JFrame("Amit");

UIManager.setLookAndFeel(UIManager.getLookAndFeel());

CalculatorApp calculator = new CalculatorApp();

textField = new JTextField(16);

textField.setEditable(false);

JButton btn0, btn1, btn2, btn3, btn4, btn5, btn6, btn7, btn8, btn9, btnAdd, btnSub, btnDiv, btnMul, btnDot,

btnClr, btnEq;

btn0 = new JButton("0");

btn1 = new JButton("1");

btn2 = new JButton("2");

btn3 = new JButton("3");

btn4 = new JButton("4");

btn5 = new JButton("5");

btn6 = new JButton("6");

btn7 = new JButton("7");

btn8 = new JButton("8");

btn9 = new JButton("9");

btnEq = new JButton("=");

btnAdd = new JButton("+");

btnSub = new JButton("-");

btnDiv = new JButton("/");

btnMul = new JButton("*");

btnClr = new JButton("C");

btnDot = new JButton(".");

btnMul.addActionListener(calculator);

btnDiv.addActionListener(calculator);

btnSub.addActionListener(calculator);

btnAdd.addActionListener(calculator);

btn9.addActionListener(calculator);

btn8.addActionListener(calculator);

btn7.addActionListener(calculator);

btn6.addActionListener(calculator);

btn5.addActionListener(calculator);

btn4.addActionListener(calculator);

btn3.addActionListener(calculator);

btn2.addActionListener(calculator);

btn1.addActionListener(calculator);

btn0.addActionListener(calculator);

btnDot.addActionListener(calculator);

btnClr.addActionListener(calculator);

btnEq.addActionListener(calculator);

JPanel panel = new JPanel();

panel.add(textField);

panel.add(btn7);

panel.add(btn8);

panel.add(btn9);

panel.add(btnDiv);

panel.add(btn4);

panel.add(btn5);

panel.add(btn6);

panel.add(btnMul);

panel.add(btn1);

panel.add(btn2);

panel.add(btn3);

panel.add(btnSub);

panel.add(btnDot);

panel.add(btnClr);

panel.add(btn0);

panel.add(btnAdd);

panel.add(btnEq);

    panel.setBackground(Color.red);

frame.add(panel);

frame.setSize(220, 240);

frame.show();

}

@Override

public void actionPerformed(ActionEvent e) {

String action = e.getActionCommand();

// if the value is number

if ((action.charAt(0) >= '0' && action.charAt(0) <= '9') || action.charAt(0) == '.') {

if(action.equals(".") && first.contains(".")) {

// no action

}

else if (!operator.equals(""))

second = second + action;

else

first = first + action;

textField.setText(first + operator + second);

}else if (action.charAt(0) == 'C') {

operator = second = "";

first = "0";

// set the value of text

textField.setText(first + operator + second);

}else if (action.charAt(0) == '=' && !first.equalsIgnoreCase("") && !second.equalsIgnoreCase("")) {

double result;

if (operator.equals("+"))

result = (Double.parseDouble(first) + Double.parseDouble(second));

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

result = (Double.parseDouble(first) - Double.parseDouble(second));

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

result = (Double.parseDouble(first) / Double.parseDouble(second));

else

result = (Double.parseDouble(first) * Double.parseDouble(second));

textField.setText(first + operator + second + "=" + result);

first = Double.toString(result);

operator = second = "";

} else {

if (operator.equals("") || second.equals(""))

operator = action;

else {

double result;

if (operator.equals("+"))

result = (Double.parseDouble(first) + Double.parseDouble(second));

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

result = (Double.parseDouble(first) - Double.parseDouble(second));

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

result = (Double.parseDouble(first) / Double.parseDouble(second));

else

result = (Double.parseDouble(first) * Double.parseDouble(second));

first = Double.toString(result);

operator = action;

second = "";

}

if (first.equals("")) {

first = operator = second = "";

} else if(second.equals("") && operator.equals("=")) {

operator = "";

}

textField.setText(first + operator + second);

}

}

}

OUTPUT:-