From ad0a18e8a9a8857baab91e2b2b91946a7154a60f Mon Sep 17 00:00:00 2001
From: Nick Chambers <uplime@spookyinternet.com>
Date: Mon, 17 Jan 2022 11:21:00 -0600
Subject: [PATCH] Allow for palindromes with non-alpha characters

---
 c/palindrome.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/c/palindrome.c b/c/palindrome.c
index 36b55f7..3c214e6 100644
--- a/c/palindrome.c
+++ b/c/palindrome.c
@@ -1,8 +1,18 @@
-int palindrome(const char *str, unsigned len) {
-  unsigned idx = 0;
+#include <ctype.h>
 
-  for(; idx < (len - (len % 2)) / 2; idx += 1) {
-    if(str[idx] != str[len - idx - 1]) {
+int palindrome(const char *str, unsigned len) {
+  const char *start = str;
+  const char *end = str + len - 1;
+
+  while(start < end) {
+    if(!isalpha(*start)) {
+      start += 1;
+    } else if(!isalpha(*end)) {
+      end -= 1;
+    } else if(tolower(*start) == tolower(*end)) {
+      start += 1;
+      end -= 1;
+    } else {
       return 0;
     }
   }