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_iteratorconst 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