C++ решите задачку пожалуйста

 #include  
using namespace std; 
int main() { 
    unsigned n; 
    cin >> n; 
    auto k = 1U; 
    auto sum = 0.0; 
    auto fact = 1.0; 
    double power = n; 
    for (auto k = 1U; k <= n; ++k) { 
        sum += fact / power; 
        fact *= k; 
        power *= n; 
    } 
    cout.setf(ios::fixed); 
    cout.precision(16); 
    cout << sum << '\n'; 
}