problem 10 done, and problem 7 rewritten (new is_prime algorithm)

2010-04-09 16:20:42 +02:00 · 2010-04-09 16:20:42 +02:00 · 2ba8a8aaeb
commit 2ba8a8aaeb
parent 8498165fef
4 changed files with 64 additions and 36 deletions
--- a/lib/prime.c
+++ b/lib/prime.c
@ -0,0 +1,18 @@
+
+#include "prime.h"
+#include <math.h>
+
+int is_prime(uint32_t p) {
+
+    uint32_t i, l;
+
+    if (p < 2 || (p & 1) == 0)
+        return 0;
+
+    l = ((uint32_t)sqrt(p)) + 1;
+
+    for(i=3; i < l; i+=2)
+        if (p % i == 0) return 0;
+
+    return 1;
+}