1. 门路
应用 std::filesystem::path 类来示意文件门路.
#include <iostream>#include <filesystem>namespace fs = std::filesystem;int main(){ fs::path p1("E:\\"); fs::path p2(p1 / "Program Files (x86)" / "Tesseract-OCR"); std::cout << p2; // 判断门路是否存在 if (fs::exists(p2)) { std::cout << " exists.\n"; } else { std::cout << " does not exists.\n"; }}"E:\\Program Files (x86)\\Tesseract-OCR" exists.获取、切换当前工作门路：
#include <iostream>#include <filesystem>namespace fs = std::filesystem;int main(){ // 打印当前工作门路 std::cout << fs::current_path() << '\n'; // 切换当前工作门路 fs::current_path(fs::path("C:\\")); std::cout << fs::current_path() << '\n';}"E:\\repos\\data-structure\\data-structure""C:\\"2. 文件信息
std::filesystem::file_status 类中蕴含了文件类型和权限信息.
#include <iostream>#include <filesystem>namespace fs = std::filesystem;void printFileType(const fs::file_type& type){ switch (type) { case fs::file_type::none: std::cout << "It has `not-evaluated-yet` type"; break; case fs::file_type::not_found: std::cout << "It does not exist"; break; case fs::file_type::regular: std::cout << "It is a regular file"; break; case fs::file_type::directory: std::cout << "It is a directory"; break; case fs::file_type::symlink: std::cout << "It is a symlink"; break; case fs::file_type::block: std::cout << "It is a block device"; break; case fs::file_type::character: std::cout << "It is a character device"; break; case fs::file_type::fifo: std::cout << "It is a named IPC pipe"; break; case fs::file_type::socket: std::cout << "It is a named IPC socket"; break; case fs::file_type::unknown: std::cout << "It has `unknown` type"; break; default: std::cout << "It has `implementation-defined` type"; break; } std::cout << '\n';}void printFilePermissions(const fs::perms& p){ std::cout << ((p & fs::perms::owner_read) != fs::perms::none ? "r" : "-") << ((p & fs::perms::owner_write) != fs::perms::none ? "w" : "-") << ((p & fs::perms::owner_exec) != fs::perms::none ? "x" : "-") << ((p & fs::perms::group_read) != fs::perms::none ? "r" : "-") << ((p & fs::perms::group_write) != fs::perms::none ? "w" : "-") << ((p & fs::perms::group_exec) != fs::perms::none ? "x" : "-") << ((p & fs::perms::others_read) != fs::perms::none ? "r" : "-") << ((p & fs::perms::others_write) != fs::perms::none ? "w" : "-") << ((p & fs::perms::others_exec) != fs::perms::none ? "x" : "-") << '\n';}int main(){ fs::path path("E:\\Program Files (x86)\\Tesseract-OCR"); fs::file_status stat(fs::status(path)); // 文件类型 printFileType(stat.type()); // 文件拜访权限 printFilePermissions(stat.permissions());}It is a directoryrwxrwxrwx判断文件类型时也能够应用如下函数：
bool is_block_file( std::filesystem::file_status s ) noexcept;bool is_character_file( std::filesystem::file_status s ) noexcept;bool is_directory( std::filesystem::file_status s ) noexcept;bool is_empty( const std::filesystem::path& p );bool is_fifo( std::filesystem::file_status s ) noexcept;// Equivalent to exists(s) && !is_regular_file(s) && !is_directory(s) && !is_symlink(s)bool is_other( std::filesystem::file_status s ) noexcept;bool is_regular_file( std::filesystem::file_status s ) noexcept;bool is_socket( std::filesystem::file_status s ) noexcept;bool is_symlink( std::filesystem::file_status s ) noexcept;3. 文件大小
以字节为单位.
#include <iostream>#include <filesystem>namespace fs = std::filesystem;int main(){ fs::path path("E:\\文档\\tmp.txt"); // 打印文件大小 std::uintmax_t size = fs::file_size(path); std::cout << size << " bytes\n"; // 批改文件大小：截断或应用0进行填充 fs::resize_file(path, size >> 1); size = fs::file_size(path); std::cout << size << " bytes\n";}3175 bytes1587 bytes4. 文件工夫
文件最初批改工夫：
#define _CRT_SECURE_NO_WARNINGS#include <iostream>#include <filesystem>namespace fs = std::filesystem;void printLastWriteTime(const fs::file_time_type& ft){ auto duration(ft.time_since_epoch()); std::time_t t = std::chrono::duration_cast<std::chrono::seconds>(duration).count(); std::cout << "File write time is " << std::asctime(std::localtime(&t));}int main(){ fs::path path("E:\\文档\\tmp.txt"); printLastWriteTime(fs::last_write_time(path));}File write time is Wed Aug 22 10:07:28 23905. 文件重命名
#include <iostream>#include <filesystem>namespace fs = std::filesystem;int main(){ fs::path oldPath("E:\\文档\\tmp1.txt"); fs::path newPath("E:\\文档\\temp1.txt"); std::cout << std::boolalpha << fs::exists(newPath) << '\n'; fs::rename(oldPath, newPath); std::cout << std::boolalpha << fs::exists(newPath) << '\n';}falsetrue6. 遍历目录
非递归遍历：
#include <iostream>#include <filesystem>namespace fs = std::filesystem;int main(){ fs::path dir("E:\\tmp\\test"); fs::directory_iterator it(dir); for (const auto& entry : it) { std::cout << entry.path().filename() << ": "; if (entry.is_directory()) { std::cout << "directory\n"; } else if (entry.is_regular_file()) { std::cout << "regular\n"; } else { std::cout << "other\n"; } }}"a.mp4": regular"dir": directory"test.py": regular递归遍历（深度优先）：
#include <iostream>#include <filesystem>namespace fs = std::filesystem;int main(){ fs::path dir("E:\\tmp\\test"); fs::recursive_directory_iterator it(dir); for (const auto& entry : it) { std::cout << entry.path() << ": "; if (entry.is_directory()) { std::cout << "directory\n"; } else if (entry.is_regular_file()) { std::cout << "regular\n"; } else { std::cout << "other\n"; } }}"E:\\tmp\\test\\a.mp4": regular"E:\\tmp\\test\\dir": directory"E:\\tmp\\test\\dir\\b.mp4": regular"E:\\tmp\\test\\dir\\test.c": regular"E:\\tmp\\test\\test.py": regular7. 创立目录
#include <filesystem>namespace fs = std::filesystem;int main(){ const fs::path dir("E:\\a\\b\\c"); // 主动创立缺失的父目录 fs::create_directories(dir); // 不会主动创立缺失的父目录 fs::create_directory(dir / "d");}8. 删除门路
#include <filesystem>namespace fs = std::filesystem;int main(){ // 只能删除文件或空目录 fs::remove(fs::path("E:\\a\\b\\c\\d")); // 递归删除子目录（非空亦可） fs::remove_all(fs::path("E:\\a"));}9. 拷贝文件
也能够拷贝目录.
#include <filesystem>namespace fs = std::filesystem;int main(){ const auto options = fs::copy_options::recursive | fs::copy_options::update_existing; fs::copy(fs::path("E:\\tmp\\Back"), fs::path("E:\\tmp\\Back2"), options);}拷贝选项：
enum class copy_options { none = /* unspecified */, skip_existing = /* unspecified */, overwrite_existing = /* unspecified */, update_existing = /* unspecified */, recursive = /* unspecified */, // Copy symlinks as symlinks, not as the files they point to. copy_symlinks = /* unspecified */, skip_symlinks = /* unspecified */, directories_only = /* unspecified */, // Instead of creating copies of files, create symlinks pointing to the originals. create_symlinks = /* unspecified */, // Instead of creating copies of files, create hardlinks that resolve to the same files as the originals. create_hard_links = /* unspecified */};10. 磁盘空间
std::filesystem::space_info 类中蕴含了磁盘空间信息（以字节为单位）.
#include <iostream>#include <filesystem>namespace fs = std::filesystem;void printSpaceInfo(const fs::path& dir){ constexpr int width = 14; std::cout << std::left; for (const auto s : { "Capacity", "Free", "Available", "Dir" }) { std::cout << "│ " << std::setw(width) << s << ' '; } std::cout << '\n'; fs::space_info si(fs::space(dir)); std::cout << "│ " << std::setw(width) << static_cast<std::intmax_t>(si.capacity) << ' ' << "│ " << std::setw(width) << static_cast<std::intmax_t>(si.free) << ' ' << "│ " << std::setw(width) << static_cast<std::intmax_t>(si.available) << ' ' << "│ " << dir << '\n';}int main(){ fs::path dir("E:\\Program Files (x86)\\"); printSpaceInfo(dir);}│ Capacity │ Free │ Available │ Dir│ 392730505216 │ 263828779008 │ 263828779008 │ "E:\\Program Files (x86)\\"