std::vector<std::string> strings;
    {
        std::ifstream input_file("tekst.txt");
        std::string s;
        while (std::getline(input_file,s))
            strings.push_back(s);
    }
    std::cout << "Plik zawiera liczbe linii rowna: " << strings.size() << std::endl;
    for (std::vector<std::string>::size_type i{}; i<strings.size(); ++i)
        std::cout << i+1 << ". " << strings[i] << std::endl;