1 files changed, 7 insertions, 0 deletions
diff --git a/lib/queue.h b/lib/queue.h
index c7acec1..23834ba 100644
--- a/lib/queue.h
+++ b/lib/queue.h
@@ -11,8 +11,15 @@ typedef struct ll_tag {
   struct ll_tag *next;
 } ll_t;
 
+typedef struct dll_tag {
+  double x;
+  struct dll_tag *next;
+} dll_t;
+
 void stack_push(ll_t **q, uint32_t x);
+void stack_push_d(dll_t **q, double x);
 
 uint32_t stack_pop(ll_t **q);
+double stack_pop_d(dll_t **q);
 
 bool stack_contains(const ll_t *q, uint32_t x);