j4

/*
Write a Java program using Runnable interface to blink Text on the JFrame (Use
Swing)
*/
package com.mycompany.practical_slip;

import java.awt.Color;
import java.util.Random;
import javax.swing.*;

class BlinkText implements Runnable
{
private JFrame frame;
private JLabel blink;

public BlinkText() {
    frame = new JFrame("Blink Light");
    frame.setSize(200, 200);
    blink = new JLabel("Blink");
    frame.add(blink);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

@Override
public void run() {
    Random rand = new Random();
    while(true) {
        int r = rand.nextInt(255);
        int g = rand.nextInt(255);
        int b = rand.nextInt(255);
        blink.setForeground(new Color(r, g, b));
    }
}

}

public class slip4_1
{
public static void main(String[] args) {
Thread t = new Thread(new BlinkText());
t.start();
}
}

/*
2. Write a Java program to store city names and their STD codes using an appropriate
collection and perform following operations:
i. Add a new city and its code (No duplicates)
ii. Remove a city from the collection
iii. Search for a city name and display the code
*/
package com.mycompany.practical_slip;

import java.util.*;

public class slip4_2
{
public static void main(String[] args) {
Map<String, String> cityMap = new HashMap<>();
Scanner sc = new Scanner(System.in);

    int ch;
    String code, city;
    do {
        System.out.println("Menu");
        System.out.println("1. Add City and std code.(no duplicates)");
        System.out.println("2. Remove City.");
        System.out.println("3. Search city name dsiplay std code");
        System.out.println("4. Exit");
        
        System.out.println("------------------------------");
        System.out.println("Enter your choice:");
        ch = sc.nextInt();
        sc.nextLine();
        System.out.println();
        
        switch(ch) {
            case 1: System.out.println("Enter std code.");
                code = sc.nextLine();
                System.out.println("Enter City.");
                city = sc.nextLine();
                cityMap.put(code, city);
                break;
            case 2: System.out.println("Enter std code.");
                code = sc.nextLine();
                cityMap.remove(code);
                break;
            case 3: System.out.println("Enter city:");
                city = sc.nextLine();
                code = null;
                for(Map.Entry<String, String> map : cityMap.entrySet()) {
                    if(map.getValue().equals(city))
                        code = map.getKey();
                }
                if(code != null)
                    System.out.println("Code is " + code);
                else
                    System.out.println("Not found.");
                break;
            default: System.out.println("Invalid choice.");
        }
        System.out.println("-------------------------------");
    } while(ch != 4);
}

}