diff --git a/twos.c b/twos.c
index e6dcffa..9dcbcb7 100644
--- a/twos.c
+++ b/twos.c
@@ -6,7 +6,7 @@
 
 int main(int argc, char *argv[]) {
     int num = abs(atoi(argv[1]));
-    char out[16]; 
+    char out[17] = "\0"; 
 
     if (num > 65535) {
         printf("not possible\n");