diff --git a/slides/cours_12.md b/slides/cours_12.md
index b5bfd790c19da07143f7f8155c3e9bf1d86fd8b6..787da033805d2dbca281f2e8ca05c63956f12e6a 100644
--- a/slides/cours_12.md
+++ b/slides/cours_12.md
@@ -108,11 +108,10 @@ void queue_enqueue(queue *fa, int val) {
     elmt->next = NULL;
     if (queue_is_empty(*fa)) {
         fa->head = elmt;
-        fa->tail = elmt;
     } else {
-        fa->tail->next = elmt;
-        fa->tail = elmt;
+        fa->tail->next = elmt;  
     }
+    fa->tail = elmt;
 }
 ```