exercise14_9.java

Introduction to java programming 一书中所有编程练习部分的源码

import java.awt.*;
import java.awt.event.*;
import javax.swing.border.*;
import java.applet.*;
import javax.swing.*;

public class Exercise14_9 extends JApplet implements ActionListener {
    private JTextField jtfDecimal = new JTextField();
    private JTextField jtfHex = new JTextField();
    private JTextField jtfBinary = new JTextField();
    
    public Exercise14_9() {
        JPanel p1 = new JPanel(new GridLayout(3, 1));
        p1.add(new JLabel("Decimal"));
        p1.add(new JLabel("Hexdecimal"));
        p1.add(new JLabel("Binary"));
        
        JPanel p2 = new JPanel(new GridLayout(3, 1));
        p2.add(jtfDecimal);
        p2.add(jtfHex);
        p2.add(jtfBinary);
        
        jtfDecimal.setHorizontalAlignment(JTextField.RIGHT);
        jtfHex.setHorizontalAlignment(JTextField.RIGHT);
        jtfBinary.setHorizontalAlignment(JTextField.RIGHT);
        
        getContentPane().add(p1, BorderLayout.WEST);
        getContentPane().add(p2, BorderLayout.CENTER);
        
        jtfDecimal.addActionListener(this);
        jtfHex.addActionListener(this);
        jtfBinary.addActionListener(this);
    }
    
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == jtfDecimal) {
            String hex = convertDecimalToHex(jtfDecimal.getText());
            jtfHex.setText(hex);
            
            String binary = convertDecimalToBianry(jtfDecimal.getText());
            jtfBinary.setText(binary);
        }
        else if (e.getSource() == jtfHex) {
            int decimal = convertHexToDecimal(jtfHex.getText());
            jtfDecimal.setText(decimal + "");
            
            String binary = convertDecimalToBianry(decimal + "");
            jtfBinary.setText(binary);
        }
        else if (e.getSource() == jtfBinary) {
            int decimal = convertBinaryToDecimal(jtfBinary.getText());
            jtfDecimal.setText(decimal + "");
            
            String hex = convertDecimalToHex(decimal + "");
            jtfHex.setText(hex);
        }
    }
    
        public static int convertBinaryToDecimal(String binaryString) {
        int value = binaryString.charAt(0) - '0';
        for (int i = 1; i < binaryString.length(); i++) {
            value = value * 2 + binaryString.charAt(i) - '0';
        }
        
        return value;
    }
    
    public static int convertHexToDecimal(String hexString) {
        int value = convertHexToDec(hexString.charAt(0));
        for (int i = 1; i < hexString.length(); i++) {
            value = value * 16 + hexString.charAt(i) - '0';
        }
        
        return value;
    }
    
    static int convertHexToDec(char ch) {
        if (ch == 'A')
            return 10;
        else if (ch == 'B')
            return 11;
        else if (ch == 'C')
            return 12;
        else if (ch == 'D')
            return 13;
        else if (ch == 'E')
            return 14;
        else if (ch == 'F')
            return 15;
        
        return ch - '0';
    }
    
    public static String convertDecimalToBianry(String s) {
        int value = Integer.parseInt(s);
        StringBuffer buffer = new StringBuffer();
        
        while (value != 0) {
            int bit = value % 2;
            buffer.insert(0, bit);
            value = value / 2;
        }
        
        return buffer.toString();
    }
    
    public static String convertDecimalToHex(String s) {
        int value = Integer.parseInt(s);
        StringBuffer buffer = new StringBuffer();
        
        while (value != 0) {
            int number = value % 16;
            char ch = convertToHex(number);
            buffer.insert(0, ch);
            value = value / 16;
        }
        
        return buffer.toString();
    }
    
    public static char convertToHex(int number) {
        if (number == 10)
            return 'A';
        else if (number == 11)
            return 'B';
        else if (number == 12)
            return 'C';
        else if (number == 13)
            return 'D';
        else if (number == 14)
            return 'E';
        else if (number == 15)
            return 'F';
        
        return (char)(number + '0');
    }
    
    /**This main method enables the applet to run as an application*/
    public static void main(String[] args) {
        // Create a frame
        JFrame frame = new JFrame("Exercise14_9");
        
        // Create an instance of the applet
        Exercise14_9 applet = new Exercise14_9();
        
        // Add the applet instance to the frame
        frame.getContentPane().add(applet, BorderLayout.CENTER);
        
        // Invoke init() and start()
        applet.init();
        applet.start();
        
        // Display the frame
        frame.setSize(300, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}