Calculator using Java Swing

  Instagram ID - Sritika Manjrekar

Calculator.java File

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

public class Calculator implements ActionListener {

JFrame frame;

JTextField textfield;

JButton[] numberButtons = new JButton[10];

JButton[] functionButtons = new JButton[9];

JButton addButton, subButton, mulButton, divButton;

JButton decButton, equButton, delButton, clrButton, negButton;

JPanel panel;

Font myFont = new Font("Ink Free", Font.BOLD, 30);

double num1 = 0, num2 = 0, result = 0;

char operator;

Calculator() {

frame = new JFrame("Calculator");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setSize(420, 550);

frame.setLayout(null);

textfield = new JTextField();

textfield.setBounds(50, 25, 300, 50);

textfield.setFont(myFont);

textfield.setEditable(false);

addButton = new JButton("+");

subButton = new JButton("-");

mulButton = new JButton("*");

divButton = new JButton("/");

decButton = new JButton(".");

equButton = new JButton("=");

delButton = new JButton("Delete");

clrButton = new JButton("Clear");

negButton=new JButton("(-)");

functionButtons[0] = addButton;

functionButtons[1] = subButton;

functionButtons[2] = mulButton;

functionButtons[3] = divButton;

functionButtons[4] = decButton;

functionButtons[5] = equButton;

functionButtons[6] = delButton;

functionButtons[7] = clrButton;

functionButtons[8] = negButton;

for (int i = 0; i < 9; i++) {

functionButtons[i].addActionListener(this);

functionButtons[i].setFont(myFont);

functionButtons[i].setFocusable(false);

}

for (int i = 0; i < 10; i++) {

numberButtons[i] = new JButton(String.valueOf(i));

numberButtons[i].addActionListener(this);

numberButtons[i].setFont(myFont);

numberButtons[i].setFocusable(false);

}

negButton.setBounds(50,430,100,50);

delButton.setBounds(150, 430, 100, 50);

clrButton.setBounds(250, 430, 100, 50);

panel = new JPanel();

panel.setBounds(50, 100, 300, 300);

panel.setLayout(new GridLayout(4, 4, 10, 10));

panel.add(numberButtons[1]);

panel.add(numberButtons[2]);

panel.add(numberButtons[3]);

panel.add(addButton);

panel.add(numberButtons[4]);

panel.add(numberButtons[5]);

panel.add(numberButtons[6]);

panel.add(subButton);

panel.add(numberButtons[7]);

panel.add(numberButtons[8]);

panel.add(numberButtons[9]);

panel.add(mulButton);

panel.add(decButton);

panel.add(numberButtons[0]);

panel.add(equButton);

panel.add(divButton);

frame.add(panel);

frame.add(negButton);

frame.add(delButton);

frame.add(clrButton);

frame.add(textfield);

frame.setVisible(true);

}

public static void main(String[] args) {

Calculator calc = new Calculator();

}

@Override

public void actionPerformed(ActionEvent e) {

// add number to text field

for (int i = 0; i < 10; i++) {

if (e.getSource() == numberButtons[i]) {

textfield.setText(textfield.getText().concat(String.valueOf(i)));

}

}

// for decimal function

if (e.getSource() == decButton) {

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

}

// for add function

if (e.getSource() == addButton) {

num1 = Double.parseDouble(textfield.getText());

operator = '+';

textfield.setText("");

}

// for subtraction function

if (e.getSource() == subButton) {

num1 = Double.parseDouble(textfield.getText());

operator = '-';

textfield.setText("");

}

// for multiplication function

if (e.getSource() == mulButton) {

num1 = Double.parseDouble(textfield.getText());

operator = '*';

textfield.setText("");

}

// for division function

if (e.getSource() == divButton) {

num1 = Double.parseDouble(textfield.getText());

operator = '/';

textfield.setText("");

}

// for equal

if (e.getSource() == equButton) {

num2 = Double.parseDouble(textfield.getText());

switch (operator) {

case '+':

result = num1 + num2;

break;

case '-':

result = num1 - num2;

break;

case '*':

result = num1 * num2;

break;

case '/':

result = num1 / num2;

break;

}

textfield.setText(String.valueOf(result));

num1 = result;

}

if (e.getSource() == clrButton) {

textfield.setText("");

}

if (e.getSource() == delButton) {

String string = textfield.getText();

textfield.setText("");

for (int i = 0; i < string.length() - 1; i++) {

textfield.setText(textfield.getText() + string.charAt(i));

}

}

if (e.getSource() == negButton) {

double temp=Double.parseDouble(textfield.getText());

temp*=-1;

textfield.setText(String.valueOf(temp));

}

}

}