первые н простых

#include <iostream>
#include <cmath>

using namespace std;

void eratosfen (int n)
{
  long long *arr = new long long[21474836];
  for (long long p = 0; p < 21474836; p++)
   arr[p] = p;

  int index = 0;

  for (long long p = 2; p < 21474836 && index < n; p++)
  {
    if (arr[p] != 0)
    {
      index++;
      cout << arr[p] << " ";
      for (long long j = p*p; j < 21474836; j += p)
        arr[j] = 0;
    }
  }
}

int main()
{
  int n = 0;
  cin >> n;

  eratosfen(n);
}