// CSE 143, Winter 2010, Marty Stepp
// This program contains a recursive file/directory-crawling method.

import java.io.*;     // for File
import java.util.*;   // for Scanner

public class FileCrawler {
    public static void main(String[] args) {
        Scanner console = new Scanner(System.in);
        System.out.print("Directory to crawl? ");
        String directoryName = console.nextLine();
        File f = new File(directoryName);
        crawl(f);
    }
    
    // Prints the given file/directory and any files/directories inside it.
    // Precondition: f != null and f exists
    public static void crawl(File f) {
        crawl(f, 0);
    }
    
    // This recursive "helper" method prints the given file/directory
    // and any files/directories inside it, at the given level of indentation.
    // Precondition: f != null and f exists
    private static void crawl(File f, int spaces) {
        // shared code for base and recursive case: print file name indented
        for (int i = 0; i < spaces; i++) {
            System.out.print(" ");
        }
        System.out.println(f.getName());
        
        // recursive (tricky) case: print sub-files/folders inside directory
        if (f.isDirectory()) {
            for (File subfile : f.listFiles()) {
                // System.out.print("    " * ... the number of calls);
                crawl(subfile, spaces + 4);
            }
        }
    }
}