#include <filesystem>
#include <fstream>
#include <iostream>
#include <string>
 
namespace fs = std::filesystem;
 
int main()
{
    // 存储当前路径以在退出时恢复
    const auto old_current_path = fs::current_path();
 
    // 在临时目录中创建 "sanbox" 目录
    const auto dir_sandbox = fs::temp_directory_path() / "sandbox";
 
    if (!fs::create_directory(dir_sandbox)) {
        std::cout << "ERROR #1" << '\n';
        return -1;
    }
 
    fs::current_path(dir_sandbox); // 切换到新创建的目录
 
    fs::directory_entry entry_sandbox { dir_sandbox };
    if (!entry_sandbox.exists()) {
        std::cout << "ERROR #2" << '\n';
        return -1;
    }
 
    std::cout << "Current dir: " << entry_sandbox.path().filename() << '\n';
 
    fs::path path_tmp_file = dir_sandbox / "tmp_file";
 
    std::ofstream file( path_tmp_file.string() ); // 创建常规文件
    file << "cppreference.com"; // 写 16 字节
    file.flush();
 
    fs::directory_entry entry_tmp_file{ path_tmp_file };
 
    if (entry_tmp_file.exists()) {
        std::cout << "File " << entry_tmp_file.path().filename()
                  << " has size: " << entry_tmp_file.file_size() << '\n';
    } else {
        std::cout << "ERROR #3" << '\n';
    }
 
    // 清理
    fs::current_path(old_current_path);
    fs::remove_all(dir_sandbox);
}