How to fill a vector in a separate function?

Question

C++ / C#

How to fill a vector through a function, such a problem that I don’t know what to write in return and the vector is simply not filled.

int ae(int n,vector <int> a) {
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    return 1;
  }
}

Answer 1

Pass a pointer to a vector to the function.
Stop though, why do you need return in the loop? Remove and try without it.

Answer 2

Why such a function? This is one [obviously doing] line in the code.

vector<int> ae (int n) {
  vector<int> a(n);
  for (int& x : a) cin >> x;
  return a;
}

Or

void ae (int n, vector<int>& a) {
  a.resize(n);
  for (int& x : a) cin >> x;
}