/* Prints all primes <= limit, where limit is an argument.  */

#include <stdio.h>
#include <stdlib.h>
#define NUM_PER_LINE 10

int isPrime(int n);

int main(int argc, char **argv) {
    int limit = atoi(argv[1]);
    int n, count = 0;

    for (n = 2; n <= limit; n++) {
        if (isPrime(n)) {
            printf("%8d", n);
            if (++count == NUM_PER_LINE) {
                putchar('\n');
                count = 0;
            }
        }
    }
    if (count > 0)
        putchar('\n');
    return 0;
}

int isPrime(int n) {
    int d;
    for (d = 2; d < n; d++)
        if (n % d == 0)
            return 0;
    return 1;
}