将数据存储在 memory 以供以后访问

Question

New to C++. I have a code that spins thru directories to look for a specific file (123.txt) and lists the result in a textbox. What i need to do is store these result in memory so i can access it later. An array maybe? I'm not exactly sure how that's done.

Here's the code to execute it:

outfile1.open("pxutil1.log");

    DWORD dwSize = MAX_PATH;
    char szLogicalDrives[MAX_PATH];
    DWORD dwResult = GetLogicalDriveStrings(dwSize, szLogicalDrives);
    if (dwResult == 0)
    {
        // error handling...
    }
    else if (dwResult > MAX_PATH)
    {
        // not enough buffer space...
    }
    else
    {
        for (char* szSingleDrive = szLogicalDrives; *szSingleDrive != 0; szSingleDrive += (lstrlenA(szSingleDrive) + 1))
        {
            if (GetDriveTypeA(szSingleDrive) == DRIVE_FIXED)
                FindFile(szSingleDrive);
        }
    }

Here's the code to search for 123.txt and list the restult in a logfile.

std::string dir = directory;
    if ((!dir.empty()) && (dir.back() != '\\') && (dir.back() != '/'))
        dir += '\\';

    WIN32_FIND_DATAA file;
    HANDLE search_handle = FindFirstFileA((dir + "*").c_str(), &file);
    if (search_handle == INVALID_HANDLE_VALUE)
    {
        if (GetLastError() != ERROR_FILE_NOT_FOUND)
        {
            // error handling...
            //::MessageBox(NULL, "File not found", "", MB_OK);
        }
    }
    else
    {
        do
        {
            if (file.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
            {
                if ((lstrcmpA(file.cFileName, ".") != 0) && (lstrcmpA(file.cFileName, "..") != 0))
                {
                    //FindFile(dir + file.cFileName);
                    if (!ExcludeDir(dir + file.cFileName))
                    {
                        FindFile(dir + file.cFileName);
                    }
                }
            }
            else
            {
                if (lstrcmpA(file.cFileName, "123.txt") == 0)
                {                   
                    outfile1 << dir.c_str() << endl; //write to log file                
                }
            }
        } while (FindNextFileA(search_handle, &file));

        if (GetLastError() != ERROR_NO_MORE_FILES)
        {
            ::MessageBox(NULL, "No more files", "", MB_OK);
        }

        FindClose(search_handle);
    }

I thought maybe i could add this to the code, but it doesn't work

string listOfDir[20]

std::string(dir) >> listOfDir;

Answer 1

The standard C++ language does not have overloads of operator>> to input arrays.
The following does not work:

std::cin >> listOfDir;

The C++ language does not have any functions to split a string.
The following does not work:

std::string(dir) >> listOfDir;

The compiler can't find any overload of operator>> that takes a std::string parameter and an array parameter. The statement would be equivalent of:

operator>>(std::string, std::string[]);

In summary, you'll need to write the code yourself to parse or split a string; or you can search the internet for a string library.

If you use std::vector , this code may be more useful:

std::vector<std::string> listOfDir;  
//...
listOfDir.push_back(dir);

The above code fragment appends a copy of dir to the vector listOfDir .