C++：判斷檔案夾(folder)是否存在(exist)

寫入程式, 需要在檔案夾中寫入資料, 如果檔案夾不存在, 則無法寫入, 在程式入口需要判斷;

由於屬於系統層, Windows的兩種解決方案.

參考: http://stackoverflow.com/questions/8233842/how-to-check-if-directory-exist-using-c-and-winapi
1. GetFileAttributesA()函數

DWORD d = GetFileAttributesA(const char* filename); #include <windows.h>
windows系統函數, 判斷檔案夾是否存在;

代碼:

#include <iostream>  #include <string>        #include <windows.h>        using namespace std;        bool dirExists(const std::string& dirName_in)  {      DWORD ftyp = GetFileAttributesA(dirName_in.c_str());      if (ftyp == INVALID_FILE_ATTRIBUTES)          return false;  //something is wrong with your path!            if (ftyp & FILE_ATTRIBUTE_DIRECTORY)          return true;   // this is a directory!            return false;    // this is not a directory!  }        int main(void)   {      std::string folder("./Test");            if (dirExists(folder)) {          std::cout << "Folder : " << folder << " exist!" << std::endl;      } else {          std::cout << "Folder : " << folder << " doesn't exist!" << std::endl;      }            std::string nofolder("./TestNo");            if (dirExists(nofolder)) {          std::cout << "Folder : " << nofolder << " exist!" << std::endl;      } else {          std::cout << "Folder : " << nofolder << " doesn't exist!" << std::endl;      }            return 0;  }

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2. _access()函數

int access(const char *filename, int mode); #include <io.h>

mode設為0, 判斷檔案是否存在; 返回0, 檔案存在;

代碼:

#include <iostream>  #include <string>        #include <io.h>        using namespace std;        bool dirExists(const std::string& dirName_in)  {      int ftyp = _access(dirName_in.c_str(), 0);            if (0 == ftyp)          return true;   // this is a directory!      else         return false;    // this is not a directory!  }        int main(void)   {      std::string folder("./Test");            if (dirExists(folder)) {          std::cout << "Folder : " << folder << " exist!" << std::endl;      } else {          std::cout << "Folder : " << folder << " doesn't exist!" << std::endl;      }            std::string nofolder("./TestNo");            if (dirExists(nofolder)) {          std::cout << "Folder : " << nofolder << " exist!" << std::endl;      } else {          std::cout << "Folder : " << nofolder << " doesn't exist!" << std::endl;      }            return 0;  }

作者：csdn部落格 Spike_King