diff --git a/include/ctype.h b/include/ctype.h
index 97b9737..a605d08 100644
--- a/include/ctype.h
+++ b/include/ctype.h
@@ -16,12 +16,12 @@ int   isxdigit(int);
 int   tolower(int);
 int   toupper(int);
 
-#define isalpha(a) ((unsigned)(((a)|32)-'a') < 26)
-#define isdigit(a) ((unsigned)((a)-'0') < 10)
-#define islower(a) ((unsigned)((a)-'a') < 26)
-#define isupper(a) ((unsigned)((a)-'A') < 26)
-#define isprint(a) ((unsigned)((a)-0x20) < 0x5f)
-#define isgraph(a) ((unsigned)((a)-0x21) < 0x5e)
+#define isalpha(a) ((((unsigned)(a)|32)-'a') < 26)
+#define isdigit(a) (((unsigned)(a)-'0') < 10)
+#define islower(a) (((unsigned)(a)-'a') < 26)
+#define isupper(a) (((unsigned)(a)-'A') < 26)
+#define isprint(a) (((unsigned)(a)-0x20) < 0x5f)
+#define isgraph(a) (((unsigned)(a)-0x21) < 0x5e)