C++ templates: Variadic template for creating formated string

I want to create a formating method that with given typename arguments generates a string. I'm using a variadic template for this:

template<typename T>
std::string GetFormat()
{
    std::string ret;
    if (typeid(T) == int)
        ret = "i";
    else if (typeid(T) == float)
        ret = "f";
    else
        ret = "n";

    return ret;
}

template<typename... Args>
std::string GetFormatVArgs()
{
   std::string ret;
   // for each arg in Args
   //     ret += GetFormat<arg>()
   return ret;
}

void main()
{
    std::string str = GetFormatVArgs<float, float, int>();
    std::cout << str;
}

Expected output:

ffi

How could I iterate for each typename and give it to GetFormat()?