change return value of coord_is_valid

1 files changed, 4 insertions, 4 deletions

diff --git a/lib/coordinate.c b/lib/coordinate.c
index f92c22a..26bbca5 100644
--- a/lib/coordinate.c
+++ b/lib/coordinate.c
@@ -4,19 +4,19 @@
 #include "coordinate.h"
 
 /*
- * Returns 0 if the coordinate is between a1 and h8.
+ * Returns 1 if the coordinate is between a1 and h8.
  */
 int coord_is_valid(char *s) {
     if (strnlen(s, 3) != 2)
-        return 1;
+        return 0;
 
     char col = tolower(s[0]);
     char row = tolower(s[1]);
 
     if (col >= 'a' && col <= 'h' && row >= '1' && row <= '8')
-        return 0;
+        return 1;
 
-    return 2;
+    return 0;
 }
 
 /*