// This program prompts the user for a file or directory name and shows
// a listing of all files and directories that can be reached from it
// (including subdirectories).

import java.io.*;
import java.util.*;

public class Crawler {
    public static void main(String[] args) {
        Scanner console = new Scanner(System.in);
        System.out.print("directory or file name? ");
        String name = console.nextLine();
        File f = new File(name);
        if (!f.exists()) {
            System.out.println("That file or directory does not exist");
        } else {
            print(f);
        }
    }
    
    // Prints the name of the given file. If the file is a directory,
    // recursively prints its content. Indents each subdirectory.
    // pre: f.exists() 
    public static void print(File f) {
        print(f, 0);
    }
    
    // Prints the name of the given file. If the file is a directory,
    // recursively prints its content. Prints at the given level of
    // indentation.
    // pre: f.exists()
    private static void print(File f, int indentLevel) {
        for (int i = 0; i < indentLevel; i++) {
            System.out.print("    ");
        }
        System.out.println(f.getName());
        if (f.isDirectory()) {    
            for (File subF : f.listFiles()) {
                print(subF, indentLevel + 1);
            }
        }
    }
}