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方法一：C++中比較簡(jiǎn)單的一種辦法（使用文件流打開(kāi)文件）

1 #include <iostream> 2 #include <fstream> 3 4 using namespace std; 5 6 #define FILENAME "*.dat" // 指定文件名 7 8 int main( void ) 9 { 10 fstream _file; 11 _file.open(FILENAME, ios::in); 12 if(!_file) 13 { 14 cout<<FILENAME<<"沒(méi)有被創(chuàng)建!"<<endl; 15 } 16 else 17 { 18 cout<<FILENAME<<"已經(jīng)存在!"<<endl; 19 } 20 21 cin.get(); 22 return 0; 23 }

方法二：利用C語(yǔ)言庫(kù)函數(shù)（_access）

函數(shù)原型：

　　int _access( const char *path, ?int mode ）

函數(shù)參數(shù)：

　　l? path：文件路徑

　　l? mode：讀寫(xiě)屬性

返回值（MSDN）：

?????? Each of these functions returns 0 if the file has the given mode. The function returns –1 if the named file does not exist or is not accessible in the given mode; in this case, errno is set as follows:

EACCES ?Access denied: file’s permission setting does not allow specified access.

ENOENT ?Filename or path not found.

EINVAL?? Invalid parameter.

函數(shù)功能（MSDN）：

?????? When used with files, the _access function determines whether the specified file exists and can be accessed as specified by the value of mode（見(jiàn)下圖表）. When used with directories, _access determines only whether the specified directory exists; in Windows NT, all directories have read and write access.

/* ACCESS.C: This example uses _access to check the* file named "ACCESS.C" to see if it exists and if* writing is allowed.*/#include <io.h> #include <stdio.h> #include <stdlib.h>void main( void ) {/* Check for existence */if( (_access( "ACCESS.C", 0 )) != -1 ){printf( "File ACCESS.C exists " );/* Check for write permission */if( (_access( "ACCESS.C", 2 )) != -1 )printf( "File ACCESS.C has write permission " );} }輸出： >>File ACCESS.C exists. >>File ACCESS.C has write permission

方法三：使用Windows API函數(shù)FindFirstFile(...)

　　(1) 檢查某一文件是否存在：

#include "windows.h" int main(int argc, char *argv[]) {WIN32_FIND_DATA FindFileData;HANDLE hFind;printf ("Target file is %s. ", argv[1]);hFind = FindFirstFile(argv[1], &FindFileData);if (hFind == INVALID_HANDLE_VALUE){printf ("Invalid File Handle. Get Last Error reports %d ", GetLastError ());}else{printf ("The first file found is %s ", FindFileData.cFileName);FindClose(hFind);}return 0; }

　　(2) ?檢查某一目錄是否存在：

// 目錄是否存在的檢查： BOOL CheckFolderExist(const string &strPath) {WIN32_FIND_DATA FindFileData;BOOL bValue = false;HANDLE hFind = FindFirstFile(strPath.c_str(), &FindFileData);if ((hFind != INVALID_HANDLE_VALUE) && (wfd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)){bValue = TRUE; }FindClose(hFind);return bValue; }

方法四：使用boost庫(kù)中filesystem類(lèi)庫(kù)的exists函數(shù)

#include <boost/filesystem/operations.hpp> #include <boost/filesystem/path.hpp> #include <boost/filesystem/convenience.hpp>using namespace boost::filesystem;int GetFilePath(std::string &strFilePath) {string strPath;int nRes = 0;//指定路徑 strPath = "C:\"; path full_path( initial_path() );full_path = system_complete( path(strPath, native ) );//判斷各級(jí)子目錄是否存在，不存在則需要?jiǎng)?chuàng)建if ( !exists( full_path ) ){bool bRet = create_directories(full_path);if (false == bRet){return -1;}}strFilePath = full_path.native_directory_string();return 0; }

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轉(zhuǎn)載于:https://www.cnblogs.com/MakeView660/p/6101251.html

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