Simple program to list files sorted by size in a directory recursively

Below is a simple program to list files in a directory recursively and sort them by their sizes. I am using this tool in my work for some time as I want to detect huge files in some directories to free up disk spaces by deleting them. Hopefully it will be useful for you as well and hence I am posting it here :)   I am using boost filesystem library to do the real work.

#include <iostream>                                            
#include <iterator>                                            
#include <queue>                                               
#include <vector>                                              
#include <map>                                                 
#include <algorithm>                                           
#include <boost/filesystem.hpp>                                

using namespace std;
using namespace boost::filesystem;

int main(int argc, char *argv[])
{                               
    queue<path> directories;    
    multimap<uintmax_t, path> filesizes;

    if (argc < 2) {
        cout << "Usage: " << argv[1] <<  " path\n";
        return 1;                                  
    }                                              
    path p(argv[1]);                               

    try {
        if (exists(p)){
            if (is_regular_file(p)){
                cout << file_size(p) << "  " << p << endl;
                return 0;                                 
            }

            if (!is_directory(p)) {
                return 0;
            }
            directories.push(p);
            vector <path> entries;
            path thispath;
            while (!directories.empty()) {
                thispath = directories.front();
                directories.pop();
                copy(directory_iterator(thispath), directory_iterator(), back_inserter(entries));
                for (vector <path>::iterator it = entries.begin();
                        it != entries.end(); ++it) {
                    if (!exists(*it))
                        continue;
                    if (!is_symlink(*it) && is_directory(*it)) {
                        directories.push(*it);
                    } else if (is_regular(*it)) {
                        uintmax_t file_siz = file_size(*it);
                        filesizes.insert(pair<uintmax_t, path>(file_siz, *it));
                    }
                }
                entries.clear();
            }
        }
        for (multimap<uintmax_t, path>::iterator it1 = filesizes.begin(), it2 = filesizes.end();
                it1 != it2; ++it1) {
            cout << it1->first << " " << it1->second << endl;
        }
        filesizes.clear();
    } catch(const filesystem_error & ex) {
        cout << ex.what() << '\n';
    }
    return 0;
}