C++遍历文件夹，使用boost filesystem递归遍历文件夹

#ifndef SCANALLFILES_H
#define SCANALLFILES_H
#include "boost/filesystem/operations.hpp"
#include "boost/filesystem/path.hpp"
#include <iostream>
using namespace std;

class ScanAllFiles{
public:
static const vector<string>& scanFiles(const string&,vector<string>&); //方法一,自己写递归，用filesystem里的directory_iterator
static const vector<string>& scanFilesUseRecursive(const string&,vector<string>&); //方法二，直接用boost的filesystem里的recursive_directory_iterator
};
//方法一，自己写递归
const vector<string>& ScanAllFiles::scanFiles(const string& rootPath,vector<string>& container=*(new vector<string>())){
namespace fs = boost::filesystem;
fs::path fullpath (rootPath, fs::native);
vector<string> &ret = container;

if(!fs::exists(fullpath)){return ret;}
fs::directory_iterator end_iter;  /**无参构造函数是最后那个iterator的value 摘抄如下
*If the end of the directory elements is reached, the iterator becomes equal to the end iterator value. The constructor directory_iterator() with no arguments always constructs an end iterator object, which is the only legitimate iterator to be used for the end condition. The result of operator* on an end iterator is not defined. For any other iterator value a const directory_entry& is returned. The result ofoperator-> on an end iterator is not defined. For any other iterator value a const directory_entry* is returned.
*
**/
for(fs::directory_iterator iter(fullpath);iter!=end_iter;iter++){
try{
if (fs::is_directory( *iter ) ){
std::cout<<*iter << "is dir.whose parent path is " << iter->path().branch_path() << std::endl;
ret.push_back(iter->path().string()); //递归前push_back进去一个
ScanAllFiles::scanFiles(iter->path().string(),ret);//递归，把vector也传进去
}else{
ret.push_back(iter->path().string());
std::cout << *iter << " is a file" << std::endl;
}
} catch ( const std::exception & ex ){
std::cerr << ex.what() << std::endl;
continue;
}
}
return ret;
}
//方法二，直接用boost的filesystem里的recursive_directory_iterator
const vector<string>& ScanAllFiles::scanFilesUseRecursive(const string& rootPath,vector<string>& container=*(new vector<string>())){
namespace fs = boost::filesystem;
fs::path fullpath (rootPath, fs::native);
vector<string> &ret = container;

if(!fs::exists(fullpath)){return ret;}
fs::recursive_directory_iterator end_iter;
for(fs::recursive_directory_iterator iter(fullpath);iter!=end_iter;iter++){
try{
if (fs::is_directory( *iter ) ){
std::cout<<*iter << "is dir" << std::endl;
ret.push_back(iter->path().string());
//ScanAllFiles::scanFiles(iter->path().string(),ret);
}else{
ret.push_back(iter->path().string());
std::cout << *iter << " is a file" << std::endl;
}
} catch ( const std::exception & ex ){
std::cerr << ex.what() << std::endl;
continue;
}
}
return ret;
}
#endif