Из пути к файлу вывести только имя файла

/// C++17
#include <iostream>
#include <iostream>
 
std::string get_name_file(std::string s)
{
    auto b = s.rfind('\\');
    auto e = s.rfind('.');
    if(b == std::string::npos) b = 0;
    if(e == std::string::npos) e = s.size();
    return s.substr(b + 1, e -b - 1);
}
 
///----------------------------------------------------------------------------|
/// Тест.
///----------------------------------------------------------------------------:
int main()
{   {   std::string t =
        R"("C:\Program Files(x86)\Steam\steamapps\common\Counter -
        Strike Global Offensive\csgo\panorama\fonts\FILE_NAME.txt")";
 
        std::cout << "dir = " << t << '\n' << get_name_file(t) << "\n\n";
    }
 
    {   std::string t = R"("FILE_NAME.txt")";
        std::cout << "dir = " << t << '\n' << get_name_file(t) << "\n\n";
    }
 
    {   std::string t = R"("FILE_NAME")";
        std::cout << "dir = " << t << '\n' << get_name_file(t) << "\n\n";
    }
}

/// C++17
#include <iostream>
#include <iostream>
 
std::string get_name_file(std::string s)
{
    auto b = s.find_last_of("\\/");
    auto e = s.rfind('.');
    return s.substr(b + 1, e - b - 1);
}
 
///----------------------------------------------------------------------------|
/// Тест.
///----------------------------------------------------------------------------:
int main()
{   {   std::string t =
        R"("C:\Program Files(x86)\Steam\steamapps\common\Counter -
        Strike Global Offensive\csgo\panorama\fonts/FILE_NAME.txt")";
 
        std::cout << "dir = " << t << '\n' << get_name_file(t) << "\n\n";
    }
 
    {   std::string t = R"("FILE...NAME....txt")";
        std::cout << "dir = " << t << '\n' << get_name_file(t) << "\n\n";
    }
 
    {   std::string t = R"("dir/FILE_NAME")";
        std::cout << "dir = " << t << '\n' << get_name_file(t) << "\n\n";
    }
 
    for(std::string t; true;)
    {
        do
        {   std::string t;
            std::cout << "dir = ";
            std::getline(std::cin, t);
            std::cout << get_name_file(t) << "\n\n";
        }while(t != "exit");
    }
 
}