Java Program to Design a Calculator Using Event Driven Programming Paradigm

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Aim:

To design a calculator using event driven programming paradigm of Java with the following options

  1. Decimal Manipulations
  2. Scientific Manipulations

Procedure:

  1. Import the swing packages and awt packages.
  2. Create the class scientificcalculator that implements action listener.
  3. Create the container and add controls for digits , scientific calculations and decimal Manipulations.
  4. The different layouts can be used to lay the controls.
  5. When the user presses the control , the event is generated and handled .
  6. The corresponding decimal , numeric and scientific calculations are performed.

Program:

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.event.*;
public class ScientificCalculator extends JFrame implements ActionListener 
{
JTextField tfield;
double temp, temp1, result, a;
static double m1, m2;
int k = 1, x = 0, y = 0, z = 0;
char ch;
JButton b1, b2, b3, b4, b5, b6, b7, b8, b9, zero, clr, pow2, pow3, exp,
fac, plus, min, div, log, rec, mul, eq, addSub, dot, mr, mc, mp,
mm, sqrt, sin, cos, tan;
Container cont;
JPanel textPanel, buttonpanel;
ScientificCalculator() 
{
cont = getContentPane();
cont.setLayout(new BorderLayout());
JPanel textpanel = new JPanel();
tfield = new JTextField(25);
tfield.setHorizontalAlignment(SwingConstants.RIGHT);
tfield.addKeyListener(new KeyAdapter() {
public void keyTyped(KeyEvent keyevent) {
char c = keyevent.getKeyChar();
if (c >= '0' && c <= '9') {
}
else 
{
keyevent.consume();
}
}
});
textpanel.add(tfield);
buttonpanel = new JPanel();
buttonpanel.setLayout(new GridLayout(8, 4, 2, 2));
boolean t = true;
mr = new JButton("MR");
buttonpanel.add(mr);
mr.addActionListener(this);
mc = new JButton("MC");
buttonpanel.add(mc);
mc.addActionListener(this);
mp = new JButton("M+");
buttonpanel.add(mp);
mp.addActionListener(this);
mm = new JButton("M-");
buttonpanel.add(mm);
mm.addActionListener(this);
b1 = new JButton("1");
buttonpanel.add(b1);
b1.addActionListener(this);
b2 = new JButton("2");
buttonpanel.add(b2);
b2.addActionListener(this);
b3 = new JButton("3");
buttonpanel.add(b3);
b3.addActionListener(this);
b4 = new JButton("4");
buttonpanel.add(b4);
b4.addActionListener(this);
b5 = new JButton("5");
buttonpanel.add(b5);
b5.addActionListener(this);
b6 = new JButton("6");
buttonpanel.add(b6);
b6.addActionListener(this);
b7 = new JButton("7");
buttonpanel.add(b7);
b7.addActionListener(this);
b8 = new JButton("8");
buttonpanel.add(b8);
b8.addActionListener(this);
b9 = new JButton("9");
buttonpanel.add(b9);
b9.addActionListener(this);
zero = new JButton("0");
buttonpanel.add(zero);
zero.addActionListener(this);
plus = new JButton("+");
buttonpanel.add(plus);
plus.addActionListener(this);
min = new JButton("-");
buttonpanel.add(min);
min.addActionListener(this);
mul = new JButton("*");
buttonpanel.add(mul);
mul.addActionListener(this);
div = new JButton("/");
div.addActionListener(this);
buttonpanel.add(div);
addSub = new JButton("+/-");
buttonpanel.add(addSub);
addSub.addActionListener(this);
dot = new JButton(".");
buttonpanel.add(dot);
dot.addActionListener(this);
eq = new JButton("=");
buttonpanel.add(eq);
eq.addActionListener(this);
rec = new JButton("1/x");
buttonpanel.add(rec);
rec.addActionListener(this);
sqrt = new JButton("Sqrt");
buttonpanel.add(sqrt);
sqrt.addActionListener(this);
log = new JButton("log");
buttonpanel.add(log);
log.addActionListener(this);
sin = new JButton("SIN");
buttonpanel.add(sin);
sin.addActionListener(this);
cos = new JButton("COS");
buttonpanel.add(cos);
cos.addActionListener(this);
tan = new JButton("TAN");
buttonpanel.add(tan);
tan.addActionListener(this);
pow2 = new JButton("x^2");
buttonpanel.add(pow2);
pow2.addActionListener(this);
pow3 = new JButton("x^3");
buttonpanel.add(pow3);
pow3.addActionListener(this);
exp = new JButton("Exp");
exp.addActionListener(this);
buttonpanel.add(exp);
fac = new JButton("n!");
fac.addActionListener(this);
buttonpanel.add(fac);
clr = new JButton("AC");
buttonpanel.add(clr);
clr.addActionListener(this);
cont.add("Center", buttonpanel);
cont.add("North", textpanel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent e) 
{
String s = e.getActionCommand();
if (s.equals("1"))
{
if (z == 0) 
{
tfield.setText(tfield.getText() + "1");
} 
else 
{
tfield.setText("");
tfield.setText(tfield.getText() + "1");
z = 0;
}
}
if (s.equals("2")) {
if (z == 0) {
tfield.setText(tfield.getText() + "2");
} 
else
{
tfield.setText("");
tfield.setText(tfield.getText() + "2");
z = 0;
}
}
if (s.equals("3")) {
if (z == 0) {
tfield.setText(tfield.getText() + "3");
} 
else
{
tfield.setText("");
tfield.setText(tfield.getText() + "3");
z = 0;
}
}
if (s.equals("4")) {
if (z == 0) {
tfield.setText(tfield.getText() + "4");
}
else
{
tfield.setText("");
tfield.setText(tfield.getText() + "4");
z = 0;
}
}
if (s.equals("5")) {
if (z == 0) {
tfield.setText(tfield.getText() + "5");
}
else
{
tfield.setText("");
tfield.setText(tfield.getText() + "5");
z = 0;
}
}
if (s.equals("6")) {
if (z == 0) {
tfield.setText(tfield.getText() + "6");
}
else
 {
tfield.setText("");
tfield.setText(tfield.getText() + "6");
z = 0;
}
}
if (s.equals("7")) {
if (z == 0) {
tfield.setText(tfield.getText() + "7");
} 
else
{
tfield.setText("");
tfield.setText(tfield.getText() + "7");
z = 0;
}
}
if (s.equals("8")) {
if (z == 0) {
tfield.setText(tfield.getText() + "8");
} 
else
{
tfield.setText("");
tfield.setText(tfield.getText() + "8");
z = 0;
}
}
if (s.equals("9")) {
if (z == 0) {
tfield.setText(tfield.getText() + "9");
}
else
{
tfield.setText("");
tfield.setText(tfield.getText() + "9");
z = 0;
}
}
if (s.equals("0")) 
{
if (z == 0) {
tfield.setText(tfield.getText() + "0");
}
else
{
tfield.setText("");
tfield.setText(tfield.getText() + "0");
z = 0;
}
}
if (s.equals("AC")) {
tfield.setText("");
x = 0;
y = 0;
z = 0;
}
if (s.equals("log")) 
{
if (tfield.getText().equals("")) {
tfield.setText("");
} 
else
 {
a = Math.log(Double.parseDouble(tfield.getText()));
tfield.setText("");
tfield.setText(tfield.getText() + a);
}
}
if (s.equals("1/x")) {
if (tfield.getText().equals("")) {
tfield.setText("");
} 
else
{
a = 1 / Double.parseDouble(tfield.getText());
tfield.setText("");
tfield.setText(tfield.getText() + a);
}
}
if (s.equals("Exp")) {
if (tfield.getText().equals("")) {
tfield.setText("");
} 
else
{
a = Math.exp(Double.parseDouble(tfield.getText()));
tfield.setText("");
tfield.setText(tfield.getText() + a);
}
}
if (s.equals("x^2")) {
if (tfield.getText().equals("")) {
tfield.setText("");
}
else
{
a = Math.pow(Double.parseDouble(tfield.getText()), 2);
tfield.setText("");
tfield.setText(tfield.getText() + a);
}
}
if (s.equals("x^3")) {
if (tfield.getText().equals("")) {
tfield.setText("");
} 
else
{
a = Math.pow(Double.parseDouble(tfield.getText()), 3);
tfield.setText("");
tfield.setText(tfield.getText() + a);
}
}
if (s.equals("+/-")) {
if (x == 0) {
tfield.setText("-" + tfield.getText());
x = 1;
} 
else
{
tfield.setText(tfield.getText());
}
}
if (s.equals(".")) {
if (y == 0) {
tfield.setText(tfield.getText() + ".");
y = 1;
} 
else
{
tfield.setText(tfield.getText());
}
}
if (s.equals("+")) 
{
if (tfield.getText().equals("")) 
{
tfield.setText("");
temp = 0;
ch = '+';
}
else
{
temp = Double.parseDouble(tfield.getText());
tfield.setText("");
ch = '+';
y = 0;
x = 0;
}
tfield.requestFocus();
}
if (s.equals("-")) 
{
if (tfield.getText().equals("")) 
{
tfield.setText("");
temp = 0;
ch = '-';
}
 else
 {
x = 0;
y = 0;
temp = Double.parseDouble(tfield.getText());
tfield.setText("");
ch = '-';
}
tfield.requestFocus();
}
if (s.equals("/")) {
if (tfield.getText().equals("")) 
{
tfield.setText("");
temp = 1;
ch = '/';
} 
else
{
x = 0;
y = 0;
temp = Double.parseDouble(tfield.getText());
ch = '/';
tfield.setText("");
}
tfield.requestFocus();
}
if (s.equals("*")) {
if (tfield.getText().equals("")) 
{
tfield.setText("");
temp = 1;
ch = '*';
} 
else 
{
x = 0;
y = 0;
temp = Double.parseDouble(tfield.getText());
ch = '*';
tfield.setText("");
}
tfield.requestFocus();
}
if (s.equals("MC")) 
{
m1 = 0;
tfield.setText("");
}
if (s.equals("MR")) 
{
tfield.setText("");
tfield.setText(tfield.getText() + m1);
}
if (s.equals("M+")) 
{
if (k == 1) {
m1 = Double.parseDouble(tfield.getText());
k++;
} 
else 
{
m1 += Double.parseDouble(tfield.getText());
tfield.setText("" + m1);
}
}
if (s.equals("M-")) 
{
if (k == 1) {
m1 = Double.parseDouble(tfield.getText());
k++;
} 
else
 {
m1 -= Double.parseDouble(tfield.getText());
tfield.setText("" + m1);
}
}
if (s.equals("Sqrt")) 
{
if (tfield.getText().equals("")) 
{
tfield.setText("");
} 
else
{
a = Math.sqrt(Double.parseDouble(tfield.getText()));
tfield.setText("");
field.setText(tfield.getText() + a);
}
}
if (s.equals("SIN")) 
{
if (tfield.getText().equals("")) 
{
tfield.setText("");
} 
else
{
a = Math.sin(Double.parseDouble(tfield.getText()));
tfield.setText("");
tfield.setText(tfield.getText() + a);
}
}
if (s.equals("COS")) 
{
if (tfield.getText().equals("")) 
{
tfield.setText("");
} 
else
{
a = Math.cos(Double.parseDouble(tfield.getText()));
tfield.setText("");
tfield.setText(tfield.getText() + a);
}
}
if (s.equals("TAN")) {
if (tfield.getText().equals("")) {
tfield.setText("");
} 
else
{
a = Math.tan(Double.parseDouble(tfield.getText()));
tfield.setText("");
tfield.setText(tfield.getText() + a);
}
}
if (s.equals("=")) 
{
if (tfield.getText().equals("")) 
{
tfield.setText("");
} 
else
{
temp1 = Double.parseDouble(tfield.getText());
switch (ch) 
{
case '+':
result = temp + temp1;
break;
case '-':
result = temp - temp1;
break;
case '/':
result = temp / temp1;
break;
case '*':
result = temp * temp1;
break;
}
tfield.setText("");
tfield.setText(tfield.getText() + result);
z = 1;
}
}
if (s.equals("n!")) 
{
if (tfield.getText().equals("")) 
{
tfield.setText("");
}
else
{
a = fact(Double.parseDouble(tfield.getText()));
tfield.setText("");
tfield.setText(tfield.getText() + a);
}
}
tfield.requestFocus();
}
double fact(double x) 
{
int er = 0;
if (x < 0) 
{
er = 20;
return 0;
}
double i, s = 1;
for (i = 2; i <= x; i += 1.0)
s *= i;
return s;
}
public static void main(String args[]) 
{
try
{
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
}
catch (Exception e) 
{
}
ScientificCalculator f = new ScientificCalculator();
f.setTitle("ScientificCalculator");
f.pack();
f.setVisible(true);
}
}

Output:

Result:

Thus the java programs for scientific calculator has been implemented and executed successfully.

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