C++ 判斷資料夾是否存在（Windows API）

方法：GetFileAttributesA

#include <windows.h>
bool dirExists(const string& path) {
    DWORD attr = GetFileAttributesA(path.c_str());
    if (attr == INVALID_FILE_ATTRIBUTES) return false;
    return (attr & FILE_ATTRIBUTE_DIRECTORY) != 0;
}

完整程式碼

#include <iostream>
#include <string>
#include <windows.h>
using namespace std;

bool dirExists(const string& dirName) {
    DWORD ftyp = GetFileAttributesA(dirName.c_str());
    if (ftyp == INVALID_FILE_ATTRIBUTES) return false;
    return (ftyp & FILE_ATTRIBUTE_DIRECTORY) != 0;
}

int main() {
    string folder("./Test");
    if (dirExists(folder)) cout << "Folder: " << folder << " exist!" << endl;
    else cout << "Folder: " << folder << " doesn't exist!" << endl;

    string nofolder("./TestNo");
    if (dirExists(nofolder)) cout << "Folder: " << nofolder << " exist!" << endl;
    else cout << "Folder: " << nofolder << " doesn't exist!" << endl;
    return 0;
}

替代方案

• C++17 std::filesystem::exists / is_directory（跨平台、推薦）。
• PathFileExists (Shlwapi.lib) 同時檢查檔案/目錄。
• FindFirstFile 同樣可用，但較重。