/*
- * Sherlock Library -- Prime Number Tests
+ * UCW Library -- Prime Number Tests
*
- * (c) 1997 Martin Mares, <mj@atrey.karlin.mff.cuni.cz>
+ * (c) 1997 Martin Mares <mj@ucw.cz>
+ *
+ * This software may be freely distributed and used according to the terms
+ * of the GNU Lesser General Public License.
*/
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "lib.h"
+#include "lib/lib.h"
static int /* Sequential search */
__isprime(uns x) /* We know x != 2 && x != 3 */
}
uns
-nextprime(uns x) /* Returns some prime greater than X, usually the next one or the second next one */
+nextprime(uns x) /* Returns some prime greater than x */
{
x += 5 - (x % 6); /* x is 6k-1 */
for(;;)
{
- if (__isprime(x))
- return x;
x += 2; /* 6k+1 */
if (__isprime(x))
return x;
x += 4; /* 6k-1 */
+ if (__isprime(x))
+ return x;
}
}
-#ifdef PRIME_DEBUG
+#ifdef TEST
+
+#include <stdio.h>
+#include <stdlib.h>
int
main(int argc, char **argv)
{
uns k = atol(argv[1]);
- if (isprime(k))
- printf("%d is prime\n");
- else
- printf("Next prime is %d\n", nextprime(k));
+ printf("%d is%s prime\n", k, isprime(k) ? "" : "n't");
+ printf("Next prime is %d\n", nextprime(k));
+ return 0;
}
#endif