Currency_converter.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.text.DecimalFormat;
import java.util.Scanner;
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author Pester Mbhetse
 */


public class Currency_converter extends JFrame {
    private JLabel amountLabel, fromLabel, toLabel, resultLabel;
    private JTextField amountField;
    private JComboBox<String> fromComboBox, toComboBox;
    private JButton convertButton, clearButton, exitButton;
    private DecimalFormat decimalFormat = new DecimalFormat("#,##0.00");

    private final String[] currencies = {"USD", "EUR", "JPY", "GBP", "CAD", "AUD", "CHF", "CNY", "INR", "ZAR"};
    private double[] exchangeRates = {1.00, 0.84, 109.65, 0.72, 1.27, 1.30, 0.92, 6.47, 87.14, 19.5};

    public Currency_converter() {
        setTitle("Currency Converter");
        setLayout(new GridLayout(5, 2));

        amountLabel = new JLabel("Amount:");
        add(amountLabel);

        amountField = new JTextField();
        add(amountField);

        fromLabel = new JLabel("From:");
        add(fromLabel);

        fromComboBox = new JComboBox<>(currencies);
        add(fromComboBox);

        toLabel = new JLabel("To:");
        add(toLabel);

        toComboBox = new JComboBox<>(currencies);
        add(toComboBox);

        convertButton = new JButton("Convert");
        add(convertButton);

        clearButton = new JButton("Clear");
        add(clearButton);

        exitButton = new JButton("Exit");
        add(exitButton);

        resultLabel = new JLabel();
        add(resultLabel);

        convertButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                try {
                    double amount = Double.parseDouble(amountField.getText());
                    String fromCurrency = (String) fromComboBox.getSelectedItem();
                    String toCurrency = (String) toComboBox.getSelectedItem();
                    double exchangeRate = exchangeRates[getIndex(toCurrency)] / exchangeRates[getIndex(fromCurrency)];
                    double result = amount * exchangeRate;
                    resultLabel.setText(decimalFormat.format(result) + " " + toCurrency);
                } catch (Exception ex) {
                    resultLabel.setText("Invalid input");
                }
            }
        });

        clearButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                clearFields();
            }
        });

        exitButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                exitApplication();
            }
        });

        setSize(300, 200);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    private int getIndex(String currency) {
        for (int i = 0; i < currencies.length; i++) {
            if (currency.equals(currencies[i])) {
                return i;
            }
        }
        return -1;
    }

    private void clearFields() {
        amountField.setText("");
        resultLabel.setText("");
    }

    private void exitApplication() {
        System.exit(0);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new Currency_converter());
    }
}