diff --git a/sk1/compressor.c b/sk1/compressor.c
index c48d9ab..3b1d122 100644
--- a/sk1/compressor.c
+++ b/sk1/compressor.c
@@ -1,5 +1,5 @@
 #include <stdio.h>
-
+#include <stdlib.h>
 #define WSIZE 250
 #define BSIZE 50