--- a/tree.c
+++ b/tree.c
@@ -7,7 +7,7 @@
 #include <stdlib.h>
 #include <time.h>
 
-#define GETRANDOM(max) (1+(int)((float)max*rand()/RAND_MAX+1.0))
+#define GETRANDOM(max) (1+(int)((float)(max)*rand()/RAND_MAX+1.0))
 
 struct T {
     int data;