To select the second index, use the setSelectedIndex() method −JList new JList(sports); list.setSelectedIndex(2);The following is an example to select the second index in Java JList −Examplepackage my; import java.awt.event.*; import java.awt.*; import javax.swing.*; class SwingDemo extends JFrame {    static JFrame frame;    static JList list;    public static void main(String[] args) {       frame = new JFrame("JList Demo");       SwingDemo s = new SwingDemo();       JPanel panel = new JPanel();       String sports[]= { "Cricket","Football","Hockey","Rugby"};       list = new JList(sports);       list.setSelectedIndex(2);       panel.add(list);       frame.add(panel);       frame.setSize(400,400);       frame.setVisible(true);    } }Output

The following is an example to create JRadioButton from text −Examplepackage my; import java.awt.FlowLayout; import java.awt.event.KeyEvent; import javax.swing.ButtonGroup; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JRadioButton; public class SwingDemo {    public static void main(String[] args) {       JRadioButton radio1 = new JRadioButton("Cricket");       JRadioButton radio2 = new JRadioButton("Football");       ButtonGroup group = new ButtonGroup();       group.add(radio1);       group.add(radio2);       radio1.setSelected(true);       JFrame frame = new JFrame();       frame.setLayout(new FlowLayout());       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);       frame.add(new JLabel("Fav Sports:"));       frame.add(radio1);     ... Read More

To add background image to JFrame, use the getImage() method of the Image class −Image img = Toolkit.getDefaultToolkit().getImage("E:\rahul.jpg");Now, draw the image −public void paintComponent(Graphics g) {    super.paintComponent(g);    g.drawImage(img, 0, 0, null); }The following is an example to add Background Image to JFrame −Exampleimport java.awt.Graphics; import java.awt.Image; import java.awt.Toolkit; import java.io.IOException; import javax.swing.JPanel; public class SwingDemo extends javax.swing.JFrame {    Image img = Toolkit.getDefaultToolkit().getImage("E:\rahul.jpg");    public SwingDemo() throws IOException {       this.setContentPane(new JPanel() {          @Override          public void paintComponent(Graphics g) {             super.paintComponent(g);     ... Read More

To create a JFrame with no border and title bar, use setUndecorated() −JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setPreferredSize(new Dimension(400, 300)); frame.setUndecorated(true);The following is an example to create JFrame with no border and title bar −Exampleimport java.awt.Dimension; import java.awt.event.ActionEvent; import javax.swing.AbstractAction; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; public class SwingDemo {    public static void main(String[] args) {       JFrame frame = new JFrame();       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);       frame.setPreferredSize(new Dimension(400, 300)); frame.setUndecorated(true);       JPanel panel = new JPanel();       panel.add(new JLabel("Demo!"));       panel.add(new JButton(new AbstractAction("Close") {   ... Read More

Here, we are activating a frame. For deactivation, we have used dispose −Thread.sleep(2000); frame.setVisible(false);The frame first activates and then deactivates after 2 seconds since we have set sleep to 2000 miliseconds.The following is an example to activate and deactivate JFrame −Exampleimport java.awt.Frame; import javax.swing.JFrame; import javax.swing.JLabel; public class SwingDemo {    public static void main(String[] args) throws InterruptedException {       JFrame frame = new JFrame();       frame.add(new JLabel("Demo"));       frame.pack();       frame.setVisible(true);       Thread.sleep(2000);       frame.setState(Frame.ICONIFIED);       Thread.sleep(2000);       frame.setVisible(false);       frame.dispose(); ... Read More

To get directories from JFileChoose, use the mode setFileSelectionMode −JFileChooser file = new JFileChooser(); file.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);The following is an example to get Directories from JFileChooser −Exampleimport javax.swing.JFileChooser; public class SwingDemo {    public static void main(String[] args) {       JFileChooser file = new JFileChooser(); file.setMultiSelectionEnabled(false);          file.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);       int res = file.showOpenDialog(null);       if (res == JFileChooser.APPROVE_OPTION) { java.io.File f = file.getSelectedFile();          System.err.println(f.getPath());       }    } }Output

The following is an example to display the contents of a text file in JTextArea −Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class SwingDemo {    private JFrame mainFrame;    private JLabel statusLabel;    private JPanel controlPanel;    public SwingDemo() {       prepareGUI();    }    public static void main(String[] args) {       SwingDemo demo = new SwingDemo();       demo.showTextAreaDemo();    }    private void prepareGUI() {       mainFrame = new JFrame("Java Swing");       mainFrame.setSize(400, 400);       mainFrame.setLayout(new GridLayout(3, 1));       mainFrame.addWindowListener(new WindowAdapter() {     ... Read More

To create FileFilter, use the FileNamExtensionFilter class. The following is an example to display File Type in JFileChooser −Exampleimport javax.swing.JFileChooser; import javax.swing.filechooser.FileNameExtensionFilter; public class SwingDemo {    public static void main(String[] args) {       JFileChooser file = new JFileChooser();       file.setAcceptAllFileFilterUsed(false);       FileNameExtensionFilter extFilter = new FileNameExtensionFilter("JPEG file", "jpg", "jpeg");       file.addChoosableFileFilter(extFilter);       file.showOpenDialog(null);    } }Output

Here we will see the fesetround() and fegetround() method in C++. These methods can be found in the cfenv library.The fesetround() method is used to set the specified floating point rounding direction to the current rounding direction. This is used with rint(), nearbyint() and some other rounding functions in C++.The syntax is like below −int fesetround(int round);The round can be among these FE_TONEAREST, FE_DOWNWARD, FE_UPWARD etc. This function returns 0 when rounding direction is successfully applied to the required manner.Example#include #include #include using namespace std; main() {    double x = 4.7, ans;    fesetround(FE_TONEAREST); //round to ... Read More

In C++, we can use the function overloading techniques. But if some base class has one method in overloaded form (different function signature with the same name), and the derived class redefines one of the function which is present inside the base, then all of the overloaded version of that function will be hidden from the derived class.Let us see one example to get the clear idea.Example#include using namespace std; class MyBaseClass {    public:       void my_function() {          cout