typo

slides/cours_10.md

@@ -75,8 +75,8 @@ bool stack_is_empty(stack s); // reutrn NULL == stack;
 void stack_push(stack *s, int val) {
     element *elem = malloc(sizeof(*elem));
     elem->data = val;
-    elem->next = *stack;
-    stack = elem;
+    elem->next = *s;
+    s = elem;
 }
 ```