vault backup: 2023-10-13 14:58:36

Algo/Courses/Chapter 6 - Lists (Exercises).md

@@ -183,4 +183,18 @@ val delete: int -> 'a list -> list = <fun>
 	else if i > length list then
 		failwith "Out of bound"
 	else
+
+(* Correction *)
+let insert_nth w i list =
+	if i <= 0 then
+		invalid_arg "negative rank"
+	else
+		let rec insrec i = function
+			[] -> if i > 1 then
+					failwith "out of bound"
+				else
+					x::t
+			| e::E when i = 1 -> x::e::t
+			| e::t -> e::insrec (i - 1) t
+		in insrec i list;;