Use C++11's constexpr to achieve string switch

C++11_string_swtich.cpp

// http://stackoverflow.com/a/107657
constexpr unsigned long long int HashStringToInt(const char *str, unsigned long long int hash = 0)
{
    return (*str == 0) ? hash : 101 * HashStringToInt(str + 1) + *str;
}

void simple_switch(const std::string &str)
{
    switch (HashStringToInt(str.c_str()))
    {
    case HashStringToInt("first"):
        std::cout << "first case" << std::endl;
        break;
        
    case SimpleStringToInt("second"):
        std::cout << "second case" << std::endl;
        break;

    default:
        break;
    }
}