#include <iostream>
using namespace std;
/*** Print positive primes <= a user-supplied value ***/
/*** Selected lines are numbered for later reference. ***/
int main() {
        unsigned posPrime, // possible prime
                 posDiv,   // possible divisor
                 n;        // user supplied limit
        // get nonzero limit
        do {
          cout << "Limit? (> 0, please) ";
          cin >> n;
        } while ( n <= 0 );

        cout << "Primes <= " << n << endl;
/* 1 */ for ( posPrime = 2; posPrime <= n; posPrime++ ) {
           // look for a divisor of a possible prime
/* 2 */    for ( posDiv = 2; posDiv < posPrime; posDiv++ ) 
             // if the divisor divides the candidate with 
             // zero remainder, the candidate is not prime
/* 3 */      if ( 0 == posPrime % posDiv ) 
               break; // stop looking -- not a prime
           // no divisors, hence we have a prime
/* 4 */    if ( posDiv == posPrime )
             cout << posPrime << endl;
        }
        return 0;
}