/* Test n, reverse(n) for primeness. */
#include <stdio.h>
int reverse(int n);

int main() {
    int	i, limit, n, r;
    printf("Enter limit: ");
    scanf("%d", &limit);
    for (n = 2; n <= limit; ++n) {

	/* Test if 'n' is prime. */
	for (i = 2; i < n; ++i) {
	    if (n % i == 0) break;
	}
	if (i != n) continue; /* Not prime */

	r = reverse(n);

	/* Test if 'r' is prime. */
	for (i = 2; i < r; ++i) {
	    if (r % i == 0) break;
	}
	if (i != r) continue; /* Not prime */

	printf("%d and %d are prime.\n",
	       n, r);
    }
    return 0;
}