Programming Articles - Page 2640 of 3366

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

In C++, the friendship is not inherited. It means that, if one parent class has some friend functions, then the child class will not get them as friend.In this example it will generate an error because the display() function is friend of MyBaseClass but not the friend of MyDerivedClass. The display() can access the private member of MyBaseClass.Example#include using namespace std; class MyBaseClass {    protected:       int x;    public:       MyBaseClass() {          x = 20;       }       friend void display(); }; class MyDerivedClass : public MyBaseClass {    private:       int y;    public:       MyDerivedClass() {          x = 40;       } }; void display() {    MyDerivedClass derived;    cout

Here we will see how we can extend some namespace, and how the unnamed or anonymous name space can be used.Sometimes we can define one namespace. Then we can write the namespace again with the same definition. If the first one has some member, and second one has some other members, then the namespace is extended. We can use all of the members from that namespace.Example#include using namespace std; namespace my_namespace {    int my_var = 10; } namespace my_namespace { //extending namespace    int my_new_var = 40; } main() {    cout

In every C/C++ program, execution starts from the main() function. Defining multiple main() functions will result in a compilation error. Can main() be Overloaded in C++? No, we cannot overload the main() function in C++ because main() serves as the entry point of any C++ program and must follow a predefined prototype. While C++ does support function overloading (i.e., multiple functions with the same name but different parameters), this does not apply to the main() function. If you try to create multiple main() functions will result in a compilation error due to invalid overloading. The following are the only two ... Read More