#include <stdio.h>
/* Is the int at argv[1] prime? */
int isprime(int n) {
  /* return 0 for false, 1 for true (usual C convention) */
  int i;
  if (n < 0) n *= -1;
  for (i=2; i<n; i++) {
    if (n % i == 0) return 0;
  }
  return (n>1);
}
main(argc, argv)
     int argc;
     char *argv[];
{
  if (isprime(atoi(argv[1]))) printf("%s is prime\n", argv[1]);
  else printf("%s is not prime\n", argv[1]);
}