Java-GUI-Calculator/Calculator.java at master · Amishakul/Java-GUI-Calculator · GitHub

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packagepa;
importjavax.swing.*;
importjava.awt.*;
importjava.awt.event.*;

publicclassCalculatorextendsJFrameimplementsActionListener {

privateJTextFielddisplayField;
privateJButton[] numberButtons;
privateJButton[] operatorButtons;
privateJButtondecimalButton;
privateJButtonclearButton;
privateJButtonequalsButton;

privatedoublefirstNumber;
privateStringoperator;
privatebooleanhasFirstNumber;
privatebooleanhasOperator;

publicCalculator() {
setTitle("Calculator");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setIconImage(newImageIcon("image.png").getImage());


displayField = newJTextField();
displayField.setPreferredSize(newDimension(300, 50));
displayField.setEditable(false);
add(displayField, BorderLayout.NORTH);

JPanelbuttonPanel = newJPanel();
buttonPanel.setLayout(newGridBagLayout());

GridBagConstraintsgbc = newGridBagConstraints();
gbc.insets = newInsets(5, 5, 5, 5);

numberButtons = newJButton[10];
for (inti = 0; i < 10; i++) {
numberButtons[i] = newJButton(String.valueOf(i));
numberButtons[i].setPreferredSize(newDimension(50, 50));
numberButtons[i].addActionListener(this);
gbc.gridx = i % 3;
gbc.gridy = 3 - (i / 3);
buttonPanel.add(numberButtons[i], gbc);
 }

operatorButtons = newJButton[5];
operatorButtons[0] = newJButton("+");
operatorButtons[1] = newJButton("-");
operatorButtons[2] = newJButton("*");
operatorButtons[3] = newJButton("/");
operatorButtons[4] = newJButton("%");

for (inti = 0; i < 5; i++) {
operatorButtons[i].setPreferredSize(newDimension(50, 50));
operatorButtons[i].addActionListener(this);
gbc.gridx = 3;
gbc.gridy = 4 - i;
buttonPanel.add(operatorButtons[i], gbc);
 }

decimalButton = newJButton(".");
decimalButton.setPreferredSize(newDimension(50, 50));
decimalButton.addActionListener(this);
gbc.gridx = 0;
gbc.gridy = 0;
buttonPanel.add(decimalButton, gbc);

clearButton = newJButton("C");
clearButton.setPreferredSize(newDimension(50, 50));
clearButton.addActionListener(this);
gbc.gridx = 1;
gbc.gridy = 0;
buttonPanel.add(clearButton, gbc);

equalsButton = newJButton("=");
equalsButton.setPreferredSize(newDimension(50, 50));
equalsButton.addActionListener(this);
gbc.gridx = 2;
gbc.gridy = 0;
buttonPanel.add(equalsButton, gbc);

add(buttonPanel, BorderLayout.CENTER);

pack();
setSize(400, 500);
setVisible(true);
 }

@Override
publicvoidactionPerformed(ActionEvente) {
Objectsource = e.getSource();

if (source == clearButton) {
displayField.setText("");
hasFirstNumber = false;
hasOperator = false;
 } elseif (source == decimalButton) {
StringcurrentText = displayField.getText();
if (!currentText.contains(".")) {
displayField.setText(currentText + ".");
 }
 } elseif (source == equalsButton) {
if (!hasFirstNumber) {
displayField.setText("Error: Enter operator");
return;
 }

StringsecondNumberString = displayField.getText();
if (secondNumberString.isEmpty()) {
displayField.setText("Error: Enter second number");
return;
 }
doublesecondNumber;
try {
secondNumber = Double.parseDouble(secondNumberString);
 } catch (NumberFormatExceptionex) {
displayField.setText("Error: Invalid second number");
return;
 }

doubleresult = 0.0;
if (operator.equals("/") && secondNumber == 0) {
displayField.setText("Error: Cannot divide by zero");
return;
 } else {
switch (operator) {
case"+":
result = firstNumber + secondNumber;
break;
case"-":
result = firstNumber - secondNumber;
break;
case"*":
result = firstNumber * secondNumber;
break;
case"/":
result = firstNumber / secondNumber;
break;
case"%":
result = firstNumber % secondNumber;
break;
 }
 }

displayField.setText(String.valueOf(result));
 } else {
for(inti = 0; i < 10; i++) {
if (source == numberButtons[i]) {
displayField.setText(displayField.getText() + i);
return;
 }
 }

for (inti = 0; i < 5; i++) {
if (source == operatorButtons[i]) {
if (displayField.getText().isEmpty()) {
displayField.setText("Error: Enter first number");
return;
 }
if (hasOperator) {
displayField.setText("Error: Enter second number");
return;
 }
firstNumber = Double.parseDouble(displayField.getText());
operator = operatorButtons[i].getText();
displayField.setText("");
hasFirstNumber = true;
hasOperator = true;
return;
 }
 }
 }
 }

publicstaticvoidmain(String[] args) {
SwingUtilities.invokeLater(newRunnable() {
@Override
publicvoidrun() {
newCalculator();
 }
 });
 }
}