Merge pull request #4951 from MicrosoftDocs/main

6/16/2023 10:30AM Publishing

Author: huypub

docs/c-runtime-library/to-functions.md

@@ -1,9 +1,8 @@
 ---
 description: "Learn more about: to Functions"
 title: "to Functions"
-ms.date: "11/04/2016"
+ms.date: 06/15/2023
 helpviewer_keywords: ["to functions", "string conversion, to different characters", "string conversion, case", "lowercase, converting strings", "uppercase, converting strings", "case, converting", "characters, converting"]
-ms.assetid: f636a4c6-8c9f-4be2-baac-064f9dbae300
 ---
 # `to` functions
 
@@ -27,28 +26,24 @@ The **`to`** functions and macro conversions are as follows.
 | `_toupper` | `_toupper` | Converts `c` to uppercase |
 | `towupper` | None | Converts c to corresponding wide-character uppercase letter |
 
-To use the function versions of the **`to`** routines that are also defined as macros, either remove the macro definitions with `#undef` directives or don't include CTYPE.H. If you use the /Za compiler option, the compiler uses the function version of `toupper` or `tolower`. Declarations of the `toupper` and `tolower` functions are in STDLIB.H.
+To use the function versions of the **`to`** routines that are also defined as macros, either remove the macro definitions with `#undef` directives or don't include `CTYPE.H`. If you use the /Za compiler option, the compiler uses the function version of `toupper` or `tolower`. Declarations of the `toupper` and `tolower` functions are in `STDLIB.H`.
 
 The `__toascii` routine sets all but the low-order 7 bits of `c` to 0, so that the converted value represents a character in the ASCII character set. If `c` already represents an ASCII character, `c` is unchanged.
 
 The `tolower` and `toupper` routines:
 
 - Are dependent on the `LC_CTYPE` category of the current locale (`tolower` calls `isupper` and `toupper` calls `islower`).
-
 - Convert `c` if `c` represents a convertible letter of the appropriate case in the current locale and the opposite case exists for that locale. Otherwise, `c` is unchanged.
 
 The `_tolower` and `_toupper` routines:
 
 - Are locale-independent, much faster versions of `tolower` and **toupper.**
-
 - Can be used only when **isascii(**`c`**)** and either **isupper(**`c`**)** or **islower(**`c`**)**, respectively, are nonzero.
-
 - Have undefined results if `c` isn't an ASCII letter of the appropriate case for converting.
 
 The `towlower` and `towupper` functions return a converted copy of `c` if and only if both of the following conditions are nonzero. Otherwise, `c` is unchanged.
 
 - `c` is a wide character of the appropriate case (that is, for which `iswupper` or **iswlower,** respectively, is nonzero).
-
 - There's a corresponding wide character of the target case (that is, for which `iswlower` or **iswupper,** respectively, is nonzero).
 
 ## Example
@@ -63,6 +58,7 @@ The `towlower` and `towupper` functions return a converted copy of `c` if and on
 
 #include <ctype.h>
 #include <string.h>
+#include <stdio.h>
 
 char msg[] = "Some of THESE letters are Uppercase.";
 char *p;
@@ -92,5 +88,5 @@ sOME OF these LETTERS ARE uPPERCASE.
 ## See also
 
 [Data conversion](./data-conversion.md)\
-[Locale](./locale.md)\
+[`Locale`](./locale.md)\
 [`is`, `isw` routines](./is-isw-routines.md)