1// Aim: Program to perform GUI operations (Calculator).
2import javax.swing.*;
3import java.awt.*;
4import java.awt.event.ActionEvent;
5import java.awt.event.ActionListener;
6
7public class Calculator1 extends JFrame implements ActionListener {
8    private JTextField display;
9    private double num1, num2, result;
10    private char operator;
11
12    public Calculator1() {
13        setTitle("Simple Calculator");
14        setSize(400, 500);
15        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
16        setLayout(new BorderLayout());
17
18        display = new JTextField();
19        display.setEditable(false);
20        display.setFont(new Font("Arial", Font.BOLD, 24));
21        add(display, BorderLayout.NORTH);
22
23        JPanel panel = new JPanel();
24        panel.setLayout(new GridLayout(4, 4));
25
26        String[] buttons = {
27            "7", "8", "9", "/",
28            "4", "5", "6", "*",
29            "1", "2", "3", "-",
30            "0", "C", "=", "+"
31        };
32
33        for (String text : buttons) {
34            JButton button = new JButton(text);
35            button.setFont(new Font("Arial", Font.BOLD, 24));
36            button.addActionListener(this);
37            panel.add(button);
38        }
39
40        add(panel, BorderLayout.CENTER);
41    }
42
43    public void actionPerformed(ActionEvent e) {
44        String command = e.getActionCommand();
45
46        if (command.charAt(0) >= '0' && command.charAt(0) <= '9') {
47            display.setText(display.getText() + command);
48        } else if (command.charAt(0) == 'C') {
49            display.setText("");
50            num1 = num2 = result = 0;
51            operator = '\0';
52        } else if (command.charAt(0) == '=') {
53            num2 = Double.parseDouble(display.getText());
54            switch (operator) {
55                case '+':
56                    result = num1 + num2;
57                    break;
58                case '-':
59                    result = num1 - num2;
60                    break;
61                case '*':
62                    result = num1 * num2;
63                    break;
64                case '/':
65                    try {
66                        result = num1 / num2;
67                    } catch (ArithmeticException ex) {
68                        display.setText("Error");
69                        return;
70                    }
71                    break;
72            }
73            display.setText(String.valueOf(result));
74        } else {
75            if (!display.getText().isEmpty()) {
76                num1 = Double.parseDouble(display.getText());
77                operator = command.charAt(0);
78                display.setText("");
79            }
80        }
81    }
82
83    public static void main(String[] args) {
84        SwingUtilities.invokeLater(() -> {
85            Calculator1 calculator = new Calculator1();
86            calculator.setVisible(true);
87        });
88    }
89}