#include <cstdlib>     //  for use of atoi function
#include <iostream>
#include <list>
using namespace std;

int
main( int argc, char* argv[] )
{
  //  Check a command-line argument is provided.
  if ( argc !=2 )
    {
      cerr << "Usage:  " << argv[0] << " n" << "\n"
           << " where n is a positive integer.\n";
      return 1;
    }

  //  Convert the C-style string to an integer using the function atoi found in cstdlib.
  int n = atoi( argv[1] );
  if ( n <= 0 )
    {
      cerr << "The argument must be a positive integer.\n";
      return 1;
    }

  //  Make a list with n integers
  list<int> primes;
  for ( int i=2; i<=n; ++i ) primes.push_back(i);

  list<int>::iterator p = primes.begin();
  while ( p != primes.end() )
    {
      cout << *p << '\n';
      list<int>::iterator q = p;
      q ++ ;   // make q refer to the next item after p
      while ( q != primes.end() )
        {
          if ( *q % *p == 0 )
            q = primes.erase(q);
          else
            ++q;
        }
      p ++ ;  // move to the next prime
    }
  return 0;
}