Simple Basic Calculator (Java) ~ BitsByta

This is a simple basic calculator in java which does functions +,-,*... Very simple GUI based, i hope it would help for the beginners...

Code

import java.awt.*;

import javax.swing.*;

import java.awt.event.*;

public class Calculator extends JFrame

implements ActionListener {

JFrame calcFrame;

Container con;

JTextField txtAnswer;

JButton btn0 , btn1 , btn2 , btn3 , btn4;

JButton btn5 , btn6 , btn7 , btn8 , btn9;

JButton btnPlus , btnMinus , btnMultiply;

JButton btnEqual , btnClear , btnPoint;

JPanel panelButtons;

JLabel calcLabel;

int num = 0;

int num1 = 0;

Integer result = 0 , tempNum = 0;

String str;

int addBit = 0 , subBit = 0 , mulBit = 0 , flag = 0 ;

public void calcInterface() {

calcFrame = new JFrame();

// Creating 0 to 9 Buttons

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");

// Creating All Operators Buttons

btnPlus = new JButton("+");

btnMinus = new JButton("-");

btnMultiply = new JButton("*");

btnEqual = new JButton("=");

btnClear = new JButton("C");

btnPoint = new JButton(".");

panelButtons = new JPanel( new GridLayout(4,4) );

panelButtons.add(btn1);

panelButtons.add(btn2);

panelButtons.add(btn3);

panelButtons.add(btnClear);

panelButtons.add(btn4);

panelButtons.add(btn5);

panelButtons.add(btn6);

panelButtons.add(btnMultiply);

panelButtons.add(btn7);

panelButtons.add(btn8);

panelButtons.add(btn9);

panelButtons.add(btnMinus);

panelButtons.add(btn0);

panelButtons.add(btnPoint);

panelButtons.add(btnPlus);

panelButtons.add(btnEqual);

con = getContentPane();

con.setLayout (new BorderLayout());

txtAnswer = new JTextField();

calcLabel = new JLabel("My Calculator In Java");

con.add(txtAnswer , BorderLayout.NORTH);

con.add(calcLabel , BorderLayout.SOUTH);

con.add(panelButtons , BorderLayout.CENTER);

setSize(300,300);

setVisible(true);

actionOnButtons();

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

// Default Constructor

public Calculator() {

calcInterface();

}

// ActionListeners of All Buttons

public void actionOnButtons() {

btn0.addActionListener(this);

btn1.addActionListener(this);

btn2.addActionListener(this);

btn3.addActionListener(this);

btn4.addActionListener(this);

btn5.addActionListener(this);

btn6.addActionListener(this);

btn7.addActionListener(this);

btn8.addActionListener(this);

btn9.addActionListener(this);

btnPlus.addActionListener(this);

btnPoint.addActionListener(this);

btnClear.addActionListener(this);

btnEqual.addActionListener(this);

btnMinus.addActionListener(this);

btnMultiply.addActionListener(this);

}

// reseting All operators(btnPlus, btnMinus , btnMultiply etc ) Bits to 0

public void resetBits() {

addBit = 0 ;

subBit = 0 ;

mulBit = 0 ;

}

//Clear All Variable values To 0 and txtAnswer =""

public void clearResult() {

num = 0;

num1 = 0;

result = 0;

txtAnswer.setText("");

resetBits();

}

public void actionPerformed (ActionEvent ae) { // Actions On All Buttons

if ( ae.getSource() == btn0) {

txtAnswer.setText(txtAnswer.getText() + "0");

str = txtAnswer.getText();