c++ - 用户指定如何保​​存数据

Question

这是一个需要将输出保存到用户指定的数据文件的程序，但是它似乎没有保存，而且我不确定为什么，我对C++来说还比较陌生，因此可以提供任何帮助

cout << "Press 's' then 'Enter' to save the file or any other key then 'Enter' to display";
cin >> save;

if (save != 's')
{
    cout << "Ix = " << Ix << "A\n";
    cout << "Iy = " << Iy << "A\n";
    cout << "Vz = " << Vz << "V\n";
}
else
{
    cout << "Please enter a name for your file: \n";
    cin >> filename;

    cout << " Please enter a directory to save your file in: \n";
    cin >> filepath;

    ofstream file((filepath + "/" + filename).c_str());

//input is being writen to the file
    file << "Ix = " << Ix << "A\n";
    file << "Iy = " << Iy << "A\n";
    file << "Vz = " << Vz << "V\n";

    file << flush;
    file.close();
}

}

Answer 1

欢迎来到SO。

打开文件流时，首先必须检查打开操作是否成功。
您可以这样做:

if(!file) { /* file isn't "good", open seems to have failed */}
/* or */
if(!file.good()) { /* file isn't good */ }

我猜是因为目录未写入任何内容(也未创建文件？)，所以目录可能不存在。 std::ofstream类将不会自动创建所需的目录。
此处详细说明了如何创建所需目录: https://en.cppreference.com/w/cpp/filesystem/create_directory