對資料夾裡面的檔案進行遍歷操作是基本技能之一，python，perl以及bash等指令碼都很好的實現了檔案遍歷方法，對於c/c++來說，只能通過系統自定的api獲取。雖然資料夾操作本身是呼叫作業系統核心的介面，但畢竟介面不夠友好。

boost不愧是準標準庫，filesystem提供了極為簡便的方法，如下所示:

[cpp] view plain copy
//  filesystem tut3.cpp  ---------------------------------------------------------------//  

//  Copyright Beman Dawes 2009  

//  Distributed under the Boost Software License, Version 1.0.  
 

//  See http://www.boost.org/LICENSE_1_0.txt  

//  Library home page: http://www.boost.org/libs/filesystem  

#include <iostream>  
#include <iterator>  
#include <algorithm>  
#include <boost/filesystem.hpp>  
using namespace std;  
using namespace boost::filesystem;  

int main(int argc, char
 
* argv[])  
{  
  if (argc < 2)  
  {  
    cout << "Usage: tut3 path\n";  
    return 1;  
  }  

  path p (argv[1]);   // p reads clearer than argv[1] in the following code  

  try  
  {  
    if (exists(p))    // does p actually exist?  
    {  
      if (is_regular_file(p))        // is p a regular file?  
 

        cout << p << " size is " << file_size(p) << '\n';  

      else if (is_directory(p))      // is p a directory?  
      {  
        cout << p << " is a directory containing:\n";  

        copy(directory_iterator(p), directory_iterator(),  // directory_iterator::value_type  
          ostream_iterator<directory_entry>(cout, "\n"));  // is directory_entry, which is  
                                                           // converted to a path by the  
                                                           // path stream inserter  
      }  
      else  
        cout << p << " exists, but is neither a regular file nor a directory\n";  
    }  
    else  
      cout << p << " does not exist\n";  
  }  

  catch (const filesystem_error& ex)  
  {  
    cout << ex.what() << '\n';  
  }  

  return 0;  
}  

然而，每次寫程式都要附上如此一大篇程式碼，很不美觀。故作了簡單封裝。
.h檔案

[cpp] view plain copy
#ifndef DIRFILEOPT_HHHH  
#define DIRFILEOPT_HHHH  

#include <iostream>  
#include <vector>  
#include <string>  

using std::vector;  
using std::string;  

class CFileOpt  
{  
private:  
    bool m_bIsDir;  
    bool m_bIsFile;  
    char* m_pFileName;  
    bool mDirOrFile();  

public:  
    CFileOpt(char*);  
    vector<string>& mGetSubFiles(vector<string>& lstpFileNames);  
    ~CFileOpt();  
};#endif  

.cpp檔案

[cpp] view plain copy
#define _SCL_SECURE_NO_WARNINGS  
#include "FileOpt.h"  
#include <iterator>  
#include <algorithm>  
#include <boost/filesystem.hpp>  
#include <boost/algorithm/string/classification.hpp>  
#include <boost/algorithm/string.hpp>  
using namespace std;  
using namespace boost::filesystem;  

bool CFileOpt::mDirOrFile()  
{  
    if(NULL == m_pFileName)  
        return false;  
    path p(m_pFileName);  
    try{  
        if(exists(p)){     
            if (is_regular_file(p))         
                m_bIsFile = true;             
            else if (is_directory(p)){  
                m_bIsDir = true;  
            }  
        }else{  
            return false;  
        }  
    }catch (const filesystem_error& ex){  
#ifdef DEBUG  
        printf(ex.what());  
#endif  
    }  
    return true;  
}  
CFileOpt::CFileOpt(char* pfilename):  
    m_pFileName(pfilename),m_bIsDir(false),m_bIsFile(false){  
        mDirOrFile();  
}  
vector<string>& CFileOpt::mGetSubFiles(vector<string>& lstpFileNames)  
{  
    if(m_bIsDir){  
        path p(m_pFileName);  
        typedef vector<path> vec;             // store paths,  
        vec pathes;  
#ifdef DEBUG  
    copy(directory_iterator(p), directory_iterator(),ostream_iterator<directory_entry>(cout,"\n"));  
#endif  
        copy(directory_iterator(p), directory_iterator(), back_inserter(pathes));  
        for(auto iter = pathes.begin();iter != pathes.end();iter ++){  
            lstpFileNames.push_back(iter->generic_string());  
        }  
        return lstpFileNames;  
    }else{  
#ifdef DEBUG  
        printf("No SubFiles In %s\n",m_pFileName);  
#endif  
    }  
    return lstpFileNames;  
}  
CFileOpt::~CFileOpt(){  
    m_pFileName = NULL;  
}  

呼叫建構函式，傳入資料夾的名字，通過mGetSubFiles()函式就可以返回資料夾內的檔案路徑