C++ String Interview Question

Question

I was recently in a C++ technical interview, where I was given a bit of simple string manipulation code, which is intended to take a string and return a string that is comprised

Answer 1

Memcpy is a cheat?

#include 
#include 
#include 

std::string first_last_n(int n, const std::string& s)
{
  if (s.size() < n)
      return "";

    char str[n*2];
    memcpy(str, s.data(), n);
    memcpy(str+n, s.data() + s.size()-n, n);

    return (const char *)str;
}

int main()
{
    std::cout << first_last_n(2, "123454321") << std::endl;
}

EDIT So I removed the other one. This is not a cheat.