Programming Articles - Page 2648 of 3366

In this scheme, pairs of letters are encrypted, instead of single letters as in the case of simple substitution cipher.In playfair cipher, initially a key table is created. The key table is a 5×5 grid of alphabets that acts as the key for encrypting the plaintext. Each of the 25 alphabets must be unique and one letter of the alphabet (usually J) is omitted from the table as we need only 25 alphabets instead of 26. If the plaintext contains J, then it is replaced by I.The sender and the receiver deicide on a particular key, say ‘tutorials’. In a ... Read More

In this scheme, pairs of letters are encrypted, instead of single letters as in the case of simple substitution cipher.In playfair cipher, initially a key table is created. The key table is a 5×5 grid of alphabets that acts as the key for encrypting the plaintext. Each of the 25 alphabets must be unique and one letter of the alphabet (usually J) is omitted from the table as we need only 25 alphabets instead of 26. If the plaintext contains J, then it is replaced by I.The sender and the receiver deicide on a particular key, say ‘tutorials’. In a ... Read More

It is a mono-alphabetic cipher wherein each letter of the plaintext is substituted by another letter to form the ciphertext. It is a simplest form of substitution cipher scheme.This cryptosystem is generally referred to as the Shift Cipher. The concept is to replace each alphabet by another alphabet which is ‘shifted’ by some fixed number between 0 and 25.For this type of scheme, both sender and receiver agree on a ‘secret shift number’ for shifting the alphabet. This number which is between 0 and 25 becomes the key of encryption.The name ‘Caesar Cipher’ is occasionally used to describe the Shift ... Read More

An automaton with a finite number of states is called a Finite Automaton. We can use a Finite State Automaton (FSA) to perform optimized pattern search operation on a string. This article will discuss how to implement a Finite State Automaton based search in C++. Problem Statement: Given two strings text[] and pattern[], we want to find all occurrences of the pattern in the text using a Finite State Automaton. // Input Strings text[] = "tutorialsPoint provides premium tutorials on various topics" pattern[] = "tutorials" // Output Pattern found at index 0 and 32 Finite State ... Read More

The JDialog Modality type APPLICATION_MODAL blocks all top-level windows and it has restrictions. The following is an example to set JDialog with Modality type APPLICATION_MODAL:Exampleimport java.awt.Cursor; import java.awt.Dialog.ModalityType; import java.awt.Dimension; import java.awt.event.ActionEvent; import javax.swing.AbstractAction; import javax.swing.JButton; import javax.swing.JDialog; import javax.swing.JFrame; public class SwingDemo {    public static void main(String[] args) {       JFrame frame = new JFrame();       frame.setSize(new Dimension(600, 400));       JDialog dialog = new JDialog(frame, "New", ModalityType.APPLICATION_MODAL);       dialog.setSize(300, 300);       frame.add(new JButton(new AbstractAction("Click to generate") {          @Override          public void ... Read More

The following is an example to pre-select JComboBox item by index in Java. Here, we have selected the 3rd item by default i.e. whenever the Swing program will run, the third item would be visible instead of the 1st.Exampleimport java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTextArea; public class SwingDemo {    public static void main(String[] args) {       JPanel panel = new JPanel(new BorderLayout());       String[] strArr = new String[] { "Laptop", "Mobile", "Desktop", "Tablet" };       JComboBox comboBox = new JComboBox(strArr);       panel.add(comboBox, ... Read More

The following is an example to display the first element in a JComboBox in Java:Exampleimport java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTextArea; public class SwingDemo {    public static void main(String[] args) {       JPanel panel = new JPanel(new BorderLayout());       String[] strArr = new String[] { "Laptop", "Mobile", "Desktop", "Tablet" };       JComboBox comboBox = new JComboBox(strArr);       panel.add(comboBox, BorderLayout.NORTH);       JTextArea text = new JTextArea(5, 5);       panel.add(text, BorderLayout.CENTER);       JButton btn = new JButton("Click");   ... Read More

To display the first element in a JComboBox, use the getSelectedIndex():comboBox.setSelectedIndex(0);The following is an example to display the first element in a JComboBox in Java:Exampleimport java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTextArea; public class SwingDemo {    public static void main(String[] args) {       JPanel panel = new JPanel(new BorderLayout());       String[] strArr = new String[] { "Laptop", "Mobile", "Desktop", "Tablet" };       JComboBox comboBox = new JComboBox(strArr);       panel.add(comboBox, BorderLayout.NORTH);       JTextArea text = new JTextArea(5, 5);       panel.add(text, ... Read More

To toggle visibility with JCheckBox, use isVisible() method:JCheckBox toggleVisibility = new JCheckBox("Hide/Show"); toggleVisibility.setSelected(comboBox.isVisible()); toggleVisibility.addItemListener(e -> {    comboBox.setVisible(e.getStateChange() == ItemEvent.SELECTED); });The following is an example to hide and display JCombobox with a JCheckBox in Java:Exampleimport java.awt.BorderLayout; import java.awt.event.ItemEvent; import javax.swing.*; public class SwingDemo {    JFrame frame;    SwingDemo(){       frame = new JFrame("ComboBox");       String Sports[]={"Select", "Tennis", "Cricket", "Football"};       JComboBox comboBox = new JComboBox(Sports);       comboBox.setBounds(50, 50, 90, 20);       frame.add(comboBox, BorderLayout.CENTER);       JCheckBox toggleVisibility = new JCheckBox("Hide/Show");       toggleVisibility.setSelected(comboBox.isVisible());       toggleVisibility.addItemListener(e ... Read More

In this article, we will learn to disable the first item on a JComboBox using Java. This setup is useful for applications where you want to show a placeholder as the first item and prevent it from being chosen, so users must select a valid option. We will be using JComboBox. JComboBox class The JComboBox class in Java is a useful component that combines a dropdown list with a button or a text field. This lets users pick an option from the list or type their input if editing is allowed. It’s great for creating forms where users can choose ... Read More