From 2b9264ecb0bb7a08b41becff9bee74e0ae33340c Mon Sep 17 00:00:00 2001 From: Steve Date: Wed, 11 Jan 2017 16:24:24 +0800 Subject: [PATCH] Luhn - add edge case description. A 0 or 1 length string is not valid, and nor is a string with non-space characters in. --- exercises/luhn/description.md | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/exercises/luhn/description.md b/exercises/luhn/description.md index d22781a1d7..2c1e6e0e69 100644 --- a/exercises/luhn/description.md +++ b/exercises/luhn/description.md @@ -7,8 +7,11 @@ The task is to write a function that checks if a given string is valid. Validating a Number ------ +Strings of length 1 or less are not valid. Spaces are allowed in the input, +but they should be stripped before checking. All other non-digit characters +are disallowed. -As an example, here is a valid (but fictitious) Canadian Social Insurance +As an example of a valid string, here is a fictitious Canadian Social Insurance Number. ```