From 9c5f0484ec80ff0c52da45f5e67be75a34e2d947 Mon Sep 17 00:00:00 2001
From: Louis <me@louisgallet.fr>
Date: Wed, 25 Oct 2023 16:43:46 +0200
Subject: [PATCH] vault backup: 2023-10-25 16:43:46

---
 Algo/Courses/Chapter 7 - X (exercises).md | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/Algo/Courses/Chapter 7 - X (exercises).md b/Algo/Courses/Chapter 7 - X (exercises).md
index 3e56df0..c326c0c 100644
--- a/Algo/Courses/Chapter 7 - X (exercises).md	
+++ b/Algo/Courses/Chapter 7 - X (exercises).md	
@@ -1,8 +1,11 @@
 ```Ocaml
 # let sum n = 
-	if n = 0 then
-		0
-	else if n < 0 then
-		failwith "input must be positive"
+	if n < 0 then
+		invalid_arg "n<0"
 	else
-		n + sum(n-1)
\ No newline at end of file
+		let rec sumrc n  =
+			if n=0 then
+				0
+			else
+				n + sum(n-1)
+		in sumrc n;;
\ No newline at end of file