1 files changed, 25 insertions, 0 deletions
diff --git a/misc.c b/misc.c
new file mode 100644
index 0000000..58c4fb7
--- /dev/null
+++ b/misc.c
@@ -0,0 +1,25 @@
+/*
+ * misc.c: Miscellaneous helpful functions.
+ */
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include "puzzles.h"
+
+int rand_upto(int limit)
+{
+    unsigned long divisor = RAND_MAX / (unsigned)limit;
+    unsigned long max = divisor * (unsigned)limit;
+    unsigned long n;
+
+    assert(limit > 0);
+
+    do {
+        n = rand();
+    } while (n >= max);
+
+    n /= divisor;
+
+    return (int)n;
+}