Fix double ended queue did not print free strings

Because it is possible for to_string function to generate a new string
here and nothing else sees it after printing it is not guaranteed to be
freed leading to a memory leak. This does mean that if the string is
internal to a struct and expected to be used later then to_string should
duplicate said string (as noted in the documentation).

1 files changed, 4 insertions, 1 deletions

diff --git a/collections/double_ended_queue/double_ended_queue.c b/collections/double_ended_queue/double_ended_queue.c
index 28ed9dc..c08169d 100644
--- a/collections/double_ended_queue/double_ended_queue.c
+++ b/collections/double_ended_queue/double_ended_queue.c
@@ -147,12 +147,15 @@ deq *root;
 char* to_string(void*);
 {
 	int i, size;;
+	char *tmp;
 
 	size = deq_size(root);
 
 	printf("[");
 	for (i = 0; i < size; i++) {
-		printf("%s,", to_string(deq_index(root, i)));
+		printf("%s,", tmp = to_string(deq_index(root, i)));
+		free(tmp);
+		tmp = NULL;
 	}
 	printf("\b]\n");
 }