#include <fstream>

std::ifstream fin(file_name);
if (!fin) {
    printf("file not exist");
    return false;
}
fin.close();

---

C++17中有std::filesystem::path，相当于Boost的filesystem模块，只需要set(CMAKE_CXX_STANDARD 17)

#include <filesystem>
#include <iostream>
namespace fs = std::filesystem;


int main()
{
    std::filesystem::path test_path("/home/user/test.yaml");
    //判断路径是否存在
    std::cout << "is_exist = " << std::filesystem::exists(test_path) << std::endl;

    // 判断路径为绝对路径还是相对路径
    std::cout << "is_abs = " << test_path.is_absolute() << std::endl;
    std::cout << "is_relative = " << test_path.is_relative() << std::endl;
    // 取得不带扩展名的文件名
    std::cout << "stem = " << test_path.stem() << std::endl;
    // 取得扩展名,如果没有,则为空
    std::cout << "extension = " << test_path.extension() << std::endl;
    // 取得文件名
    std::cout << "filename = " << test_path.filename() << std::endl;

    std::cout << "----------------------------------------" << std::endl;

    std::filesystem::path test_dir("/home/user/Pictures");
    //判断是文件还是文件夹
    std::cout << "is_file = " << std::filesystem::is_regular_file(test_path) << std::endl;
    std::cout << "is_dir = " << std::filesystem::is_directory(test_dir) << std::endl;

    //关于路径拼接
    std::filesystem::path new_path = test_dir / "test.txt";
    std::cout << "new_path = " << new_path << std::endl;

    //取得当前绝对工作路径 编译后可执行文件的路径文件夹
    std::filesystem::path workPath = std::filesystem::current_path();
    std::cout << "current exe path = " << workPath << std::endl;

    //递归遍历指定路径下所有文件,文件夹名字也会返回
    std::filesystem::recursive_directory_iterator iterDir(test_dir);
    for (auto &it: iterDir)
    {
        //打印绝对路径
        std::cout << it << std::endl;
        // 不打印路径而是打印文件名
       std::cout << it.path().filename() << std::endl;
    }

    //给一个相对路径,返回绝对路径
    std::filesystem::path path_test("./");
    std::cout << "abs_path = " << std::filesystem::absolute(path_test) << std::endl;


    // 删除文件, 路径不存在不报错
//    std::filesystem::remove(test_dir / "deepfakes"/"yolov7.pdf");

    // 拷贝文件夹, 删除文件夹
//    std::filesystem::copy(test_dir, test_dir.parent_path() / "works", std::filesystem::copy_options::recursive);
//    std::filesystem::remove_all(test_dir.parent_path() / "works");
    return 0;
}