ns4

Q1]

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

public class BlinkingText implements Runnable {
private JLabel label;

public BlinkingText() {
    JFrame frame = new JFrame("Blinking Text");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 200);
    
    label = new JLabel("Blinking Text");
    label.setFont(new Font("Arial", Font.BOLD, 20));
    frame.add(label, BorderLayout.CENTER);

    frame.setVisible(true);
}

@Override
public void run() {
    try {
        while (true) {
            Thread.sleep(500); 
            label.setVisible(!label.isVisible());
        }
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

public static void main(String[] args) {
    BlinkingText blinkingText = new BlinkingText();
    Thread thread = new Thread(blinkingText);
    thread.start();
}

}

Q2]

import java.util.*;

public class CitySTDCode {
private Map<String, Integer> citySTDMap;

public CitySTDCode() {
    citySTDMap = new HashMap<>();
}


public void addCity(String cityName, int stdCode) {
    if (!citySTDMap.containsKey(cityName)) {
        citySTDMap.put(cityName, stdCode);
        System.out.println("City '" + cityName + "' added with STD code: " + stdCode);
    } else {
        System.out.println("City '" + cityName + "' already exists in the collection.");
    }
}


public void removeCity(String cityName) {
    if (citySTDMap.containsKey(cityName)) {
        int stdCode = citySTDMap.remove(cityName);
        System.out.println("City '" + cityName + "' with STD code " + stdCode + " removed from the collection.");
    } else {
        System.out.println("City '" + cityName + "' not found in the collection.");
    }
}


public void searchCity(String cityName) {
    if (citySTDMap.containsKey(cityName)) {
        int stdCode = citySTDMap.get(cityName);
        System.out.println("STD code for city '" + cityName + "': " + stdCode);
    } else {
        System.out.println("City '" + cityName + "' not found in the collection.");
    }
}

public static void main(String[] args) {
    CitySTDCode citySTDCode = new CitySTDCode();
    citySTDCode.addCity("New York", 212);
    citySTDCode.addCity("Los Angeles", 213);
    citySTDCode.addCity("Chicago", 312);
    citySTDCode.addCity("San Francisco", 415);

    System.out.println("\nPerforming operations:");
    citySTDCode.addCity("Los Angeles", 310); 
    citySTDCode.removeCity("Chicago");
    citySTDCode.searchCity("New York");
    citySTDCode.searchCity("Houston"); 
}

}