Slip No 9 Q B

Q.Write a java program to validate PAN number and Mobile Number. If it is invalid then throw user defined Exception “Invalid Data”, otherwise display it. [25 M]

import java.io.File;
import java.util.Scanner;

public class ShowTxtFiles {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        // Accept directory path from user
        System.out.print("Enter directory path: ");
        String dirPath = sc.nextLine();

        File dir = new File(dirPath);

        // Validate directory
        if (!dir.exists() || !dir.isDirectory()) {
            System.out.println("Invalid directory path.");
            sc.close();
            return;
        }

        // Get all files in directory
        File[] files = dir.listFiles();

        System.out.println("\n.txt files present in directory:");

        // Display .txt files
        for (File f : files) {
            if (f.isFile() && f.getName().toLowerCase().endsWith(".txt")) {
                System.out.println(f.getName());
            }
        }

        sc.close();
    }
}