Notes

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Stack;

public class Calculator extends JFrame implements ActionListener {
private JTextField display;
private StringBuilder expression;

public Calculator() {
expression = new StringBuilder();

// Display field setup with "plastic" look
display = new JTextField("0");
display.setEditable(false);
display.setHorizontalAlignment(SwingConstants.RIGHT);
display.setFont(new Font("Arial", Font.BOLD, 30));
display.setBackground(new Color(240, 240, 240));
display.setBorder(BorderFactory.createLineBorder(new Color(160, 160, 160), 5)); // Simulate depth
display.setPreferredSize(new Dimension(400, 70));
display.setMargin(new Insets(10, 10, 10, 10));

// Button panel setup
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(6, 4, 10, 10));
buttonPanel.setBackground(new Color(245, 245, 245));
buttonPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));

// Button labels in desired layout order
String[] buttons = {
"7", "8", "9", "÷",
"4", "5", "6", "×",
"1", "2", "3", "-",
"0", "00", ".", "+",
"C", "Del", "√", "^",
"log", "ln", "%", "="
};

// Create and style buttons with realistic "plastic" effect
for (String text : buttons) {
JButton button = new JButton(text);
button.setFont(new Font("Arial", Font.BOLD, 20));
button.setFocusPainted(false);
button.setForeground(Color.WHITE);
button.setBorder(BorderFactory.createLineBorder(new Color(150, 150, 150), 2)); // Border to simulate depth

// Button colors based on type
if (text.matches("[0-9]") || text.equals(".")) {
button.setBackground(new Color(70, 70, 70)); // Dark buttons for numbers
}
else if ("÷×-+^√logln%".contains(text)) {
button.setBackground(new Color(240, 128, 128)); // Operators with a soft red tone
}
else if (text.equals("=")) {
button.setBackground(new Color(255, 165, 0)); // Orange for the "=" button
}
else if (text.equals("C") || text.equals("Del")) {
button.setBackground(new Color(220, 20, 60)); // Dark red for "C" and "Del"
}
else if (text.equals("00")) {
button.setBackground(new Color(80, 80, 80)); // Darker button for "00"
}

button.setPreferredSize(new Dimension(80, 80));
button.setMargin(new Insets(10, 10, 10, 10)); // Spacing for button text
button.setFont(new Font("Arial", Font.BOLD, 24));
button.addActionListener(this);
buttonPanel.add(button);
}

// Outer border for the frame (plastic effect)
JPanel outerPanel = new JPanel();
outerPanel.setLayout(new BorderLayout());
outerPanel.setBackground(new Color(245, 245, 245));
outerPanel.setBorder(BorderFactory.createLineBorder(new Color(160, 160, 160), 10)); // Outer border to simulate plastic body
outerPanel.add(display, BorderLayout.NORTH);
outerPanel.add(buttonPanel, BorderLayout.CENTER);

// Frame layout setup
setLayout(new BorderLayout(10, 10));
add(outerPanel, BorderLayout.CENTER);

// Frame properties
setTitle("Realistic Calculator");
setSize(450, 650); // Adjust size for the realistic look
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setResizable(false);
setVisible(true);
}

@Override
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();

if (command.matches("[0-9]")) {
if (display.getText().equals("0") || display.getText().equals("Error")) {
expression.setLength(0);
}
expression.append(command);
display.setText(expression.toString());
} else if (command.equals(".")) {
if (!display.getText().contains(".")) {
expression.append(command);
display.setText(expression.toString());
}
} else if (command.equals("C")) {
expression.setLength(0);
display.setText("0");
} else if (command.equals("Del")) {
if (expression.length() > 0) {
expression.deleteCharAt(expression.length() - 1);
display.setText(expression.length() > 0 ? expression.toString() : "0");
}
} else if (command.equals("=")) {
try {
double result = evaluateExpression(expression.toString());
display.setText(String.valueOf(result));
expression.setLength(0);
expression.append(result);
} catch (Exception ex) {
display.setText("Error");
expression.setLength(0);
}
} else if ("logln√^%".contains(command)) {
expression.append(" ").append(command).append(" ");
display.setText(expression.toString());
} else if (command.equals("00")) {
expression.append("00");
display.setText(expression.toString());
} else {
if (expression.length() > 0 && !isOperator(expression.charAt(expression.length() - 1))) {
expression.append(" ").append(command).append(" ");
display.setText(expression.toString());
}
}
}

private double evaluateExpression(String exp) throws Exception {
// Check for functions and handle them
if (exp.contains("log")) {
return Math.log10(parseArgument(exp, "log"));
} else if (exp.contains("ln")) {
return Math.log(parseArgument(exp, "ln"));
} else if (exp.contains("√")) {
return Math.sqrt(parseArgument(exp, "√"));
} else if (exp.contains("%")) {
return parsePercentage(exp);
} else {
Stack<Double> values = new Stack<>();
Stack<String> ops = new Stack<>();
String[] tokens = exp.split(" ");

for (String token : tokens) {
if (token.isEmpty()) continue;
if (token.matches("[0-9.]+")) {
values.push(Double.parseDouble(token));
} else if ("+-×÷^".contains(token)) {
while (!ops.isEmpty() && hasPrecedence(token, ops.peek())) {
values.push(applyOperation(ops.pop(), values.pop(), values.pop()));
}
ops.push(token);
}
}

while (!ops.isEmpty()) {
values.push(applyOperation(ops.pop(), values.pop(), values.pop()));
}

return values.pop();
}
}

private double parseArgument(String exp, String func) throws Exception {
int startIndex = exp.indexOf(func) + func.length();
String arg = exp.substring(startIndex).trim();
return Double.parseDouble(arg);
}

private double parsePercentage(String exp) {
String number = exp.replaceAll("[^0-9.]", "");
return Double.parseDouble(number) / 100;
}

private double applyOperation(String op, double b, double a) {
switch (op) {
case "+": return a + b;
case "-": return a - b;
case "×": return a * b;
case "÷":
if (b == 0) throw new ArithmeticException("Division by zero");
return a / b;
case "^": return Math.pow(a, b);
}
return 0;
}

private boolean hasPrecedence(String op1, String op2) {
if (op2.equals("(") || op2.equals(")")) return false;
if ((op1.equals("×") || op1.equals("÷") || op1.equals("^")) && (op2.equals("+") || op2.equals("-"))) return false;
return true;
}

private boolean isOperator(char c) {
return c == '+' || c == '-' || c == '×' || c == '÷' || c == '^';
}

public static void main(String[] args) {
SwingUtilities.invokeLater(Calculator::new);
}
}