Programming Articles

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How to display a value when select a JList item in Java?

raja
raja
Updated on 10-Feb-2020 2K+ Views

A JList is a subclass of JComponent class that allows the user to choose either a single or multiple selections of items. A JList can generate a ListSelectiionListener interface and it includes one abstract method valueChanged(). We can display a value when an item is selected from a JList by implementing MouseListener interface or extending MouseAdapter class and call the getClickCount() method with single-click event (getClickCount() == 1) of MouseEvent class.Exampleimport javax.swing.*; import java.awt.*; import java.awt.event.*; import java.util.*; public class JListItemSeletionTest extends JFrame {    private JList list;    private JScrollPane jsp;    private Vector data;    public JListItemSeletionTest() {       setTitle("JListItemSeletion Test");       ...

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Maximum XOR value of a pair from a range in C++

Narendra Kumar
Narendra Kumar
Updated on 10-Feb-2020 902 Views

Problem statementGiven a range [L, R], we need to find two integers in this range such that their XOR is maximum among all possible choices of two integersIf the given range is L = 1 and R = 21 then the output will be 31 as − 31 is XOR of 15 and 16 and it is maximum within range.Algorithm1. Calculate the (L^R) value 2. From most significant bit of this value add all 1s to get the final resultExample#include using namespace std; int getMaxXOR(int L, int R){    int LXR = L ^ R;    int msbPos = ...

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Maximum width of a binary tree in C++

Narendra Kumar
Narendra Kumar
Updated on 10-Feb-2020 367 Views

Problem statementGiven a binary tree, write a function to get the maximum width of the given tree. The width of a tree is the maximum of widths of all levels.Consider below tree −      10      / \     7   4    / \   \   9   2   1          / \         2   5 1. Width at level 1: 1 2. Width at level 2: 2 3. Width at level 3: 3 4. Width at level 4: 2 For above tree answer is 3.Algorithm1. Use ...

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Maximum weight transformation of a given string in C++

Narendra Kumar
Narendra Kumar
Updated on 10-Feb-2020 524 Views

Problem statementGiven a string consisting of only A’s and B’s. We can transform the given string to another string by toggling any character. Thus many transformations of the given string are possible. The task is to find the Weight of the maximum weight transformation.Weight of a sting is calculated using below formula −Weight of string = Weight of total pairs + weight of single characters - Total number of toggles.Two consecutive characters are considered a pair only if they are different.Weight of a single pair (both characters are different) = 4Weight of a single character = 1If the input string ...

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How many types of selection modes for a JList in Java?

raja
raja
Updated on 10-Feb-2020 960 Views

A JList is a component that can extend JComponent class used to display a list of objects that allows the user to select one or more items.There are three types of selection modes for a JList in JavaListSelectionModel.SINGLE_SELECTION: Only one list index can be selected at a time.ListSelectionModel.SINGLE_INTERVAL_SELECTION: Only one contiguous interval can be selected at a time.ListSelectionModel.MULTIPLE_INTERVAL_SELECTION: In this mode, there is no restriction on what can be selected. This is a default mode.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class JListSelectionModeTest extends JFrame implements ActionListener {    private JList list;    private DefaultListModel listModel;    public JListSelectionModeTest() {     ...

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How can we implement a scrollable JPanel in Java?

raja
raja
Updated on 10-Feb-2020 5K+ Views

JPanelA JPanel is a subclass of JComponent (a subclass of a Container class). Therefore, JPanel is also a Container.A JPanel is an empty area that can be used either to layout other components including other panels.In a JPanel, we can add fields, labels, buttons, checkboxes,  and images also.The Layout Managers such as FlowLayout, GridLayout, BorderLayout and other layout managers helps us to control the sizes, positions, and alignment of the components using JPanel.The important methods of a JPanel class are getAccessibleContext(), getUI(), updateUI() and paramString().We can also implement a JPanel with vertical and horizontal scrolls by adding the panel object to JScrollPane.Exampleimport java.awt.*; ...

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How can we implement editable JComboBox in Java?

raja
raja
Updated on 10-Feb-2020 2K+ Views

JComboBoxA JComboBox can extend JComponent class and it is a combination of a text field and a drop-down list from which the user can choose a value.If the text field portion of the control is editable, the user can enter a value in the field or edit a value retrieved from the drop-down list.By default, the user not allowed to edit the data in the text field portion of the JComboBox. If we want to allow the user to edit the text field, call setEditable(true) method.A JComboBox can generate an ActionListener, ChangeListener or ItemListener when the user actions on a combo box.A ...

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How to implement a program to count the number in Java?

raja
raja
Updated on 10-Feb-2020 1K+ Views

The program uses a JLabel to hold a count label, a JTextField component to hold the number count, JButton component to create add, remove and reset buttons. When we click the add button, the count in the JTextField will get incremented by '1' and by clicking the remove button the count will be decremented by '1'. If we click the Reset button, it will reset the count to '0'.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class CounterTest extends JFrame implements ActionListener { private JLabel label; private JTextField text; private JButton addBtn, ...

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How many types of JDialog boxes can be created in Java?

raja
raja
Updated on 07-Feb-2020 249 Views

A JDialog is a subclass of Dialog class and it does not hold minimize and maximize buttons at the top right corner of the window. We can create two types of JDialog boxes.in JavaModal DialogNon-Modal DialogModal JDialogIn Java, When a modal dialog window is active, all the user inputs are directed to it and the other parts of the application are inaccessible until this model dialog is closed.Non-Modal JDialogIn Java, When a non-modal dialog window is active, the other parts of the application are still accessible as normal and inputs can be directed to them, while this non-modal dialog window ...

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How can we implement line wrap and word wrap text inside a JTextArea in Java?

raja
raja
Updated on 07-Feb-2020 1K+ Views

A JTextArea is a multi-line text component to display text or allow the user to enter the text and it will generate a CaretListener interface when we are trying to implement the functionality of the JTextArea component. A JTextArea class inherits the JTextComponent class in Java.In the below example, we can implement a JTextArea class with a user can select either word wrap or line wrap checkboxes using the ItemListener interface.Exampleimport javax.swing.*; import java.awt.*; import java.awt.event.*; public class JTextAreaTest {    public static void main(String[] args ) {       EventQueue.invokeLater(new Runnable() {          @Override          public void run() {   ...

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