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iswdigit

From cppreference.com
< cβ€Ž | stringβ€Ž | wide
 
C
 
Strings library
 
Null-terminated wide strings
 
Defined in header <wctype.h>
int iswdigit( wint_t ch );
 (since C95)

Checks if the given wide character corresponds (if narrowed) to one of the ten decimal digit characters 0123456789.

Contents

[edit] Parameters

ch - wide character

[edit] Return value

Non-zero value if the wide character is a numeric character, zero otherwise.

[edit] Notes

iswdigit and iswxdigit are the only standard wide character classification functions that are not affected by the currently installed C locale.

[edit] Example

Some locales offer additional character classes that detect non-ASCII digits

Run this code
#include <locale.h>
#include <stdio.h>
#include <wchar.h>
#include <wctype.h>
 
void test(wchar_t a3, wchar_t u3, wchar_t j3)
{
    printf("\t '%lc'  '%lc' '%lc'\n", a3, u3, j3);
    printf("iswdigit: %d    %d    %d\n",
           !!iswdigit(a3),
           !!iswdigit(u3),
           !!iswdigit(j3));
    printf("jdigit:   %d    %d    %d\n",
           !!iswctype(a3, wctype("jdigit")),
           !!iswctype(u3, wctype("jdigit")),
           !!iswctype(j3, wctype("jdigit")));
}
 
int main(void)
{
    wchar_t a3 = L'3';  // the ASCII digit 3
    wchar_t u3 = L'δΈ‰'; // the CJK numeral 3
    wchar_t j3 = L'οΌ“'; // the full-width digit 3
 
    setlocale(LC_ALL, "en_US.utf8");
    puts("In American locale:");
    test(a3, u3, j3);
 
    setlocale(LC_ALL, "ja_JP.utf8");
    puts("\nIn Japanese locale:");
    test(a3, u3, j3);
}

Possible output: 

In American locale:
         '3'  'δΈ‰' 'οΌ“'
iswdigit: 1    0    0
jdigit:   0    0    0
 
In Japanese locale:
         '3'  'δΈ‰' 'οΌ“'
iswdigit: 1    0    0
jdigit:   0    0    1

[edit] References

  • C23 standard (ISO/IEC 9899:2024):
  • TBD 7.30.2.1.5 The iswdigit function (p: TBD)
  • C17 standard (ISO/IEC 9899:2018):
  • 7.30.2.1.5 The iswdigit function (p: 327)
  • C11 standard (ISO/IEC 9899:2011):
  • 7.30.2.1.5 The iswdigit function (p: 449)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.25.2.1.5 The iswdigit function (p: 395)

[edit] See also

 checks if a character is a digit
(function) [edit]
C++ documentation for iswdigit
ASCII values characters

iscntrl
iswcntrl

isprint
iswprint

isspace
iswspace

isblank
iswblank

isgraph
iswgraph

ispunct
iswpunct

isalnum
iswalnum

isalpha
iswalpha

isupper
iswupper

islower
iswlower

isdigit
iswdigit

isxdigit
iswxdigit

decimal hexadecimal octal
0–8 \x0–\x8 \0–\10 control codes (NUL, etc.) β‰ 0 0 0 0 0 0 0 0 0 0 0 0
9 \x9 \11 tab (\t) β‰ 0 0 β‰ 0 β‰ 0 0 0 0 0 0 0 0 0
10–13 \xA–\xD \12–\15 whitespaces (\n, \v, \f, \r) β‰ 0 0 β‰ 0 0 0 0 0 0 0 0 0 0
14–31 \xE–\x1F \16–\37 control codes β‰ 0 0 0 0 0 0 0 0 0 0 0 0
32 \x20 \40 space 0 β‰ 0 β‰ 0 β‰ 0 0 0 0 0 0 0 0 0
33–47 \x21–\x2F \41–\57 !"#$%&'()*+,-./ 0 β‰ 0 0 0 β‰ 0 β‰ 0 0 0 0 0 0 0
48–57 \x30–\x39 \60–\71 0123456789 0 β‰ 0 0 0 β‰ 0 0 β‰ 0 0 0 0 β‰ 0 β‰ 0
58–64 \x3A–\x40 \72–\100 :;<=>?@ 0 β‰ 0 0 0 β‰ 0 β‰ 0 0 0 0 0 0 0
65–70 \x41–\x46 \101–\106 ABCDEF 0 β‰ 0 0 0 β‰ 0 0 β‰ 0 β‰ 0 β‰ 0 0 0 β‰ 0
71–90 \x47–\x5A \107–\132 GHIJKLMNOP
QRSTUVWXYZ 		0 β‰ 0 0 0 β‰ 0 0 β‰ 0 β‰ 0 β‰ 0 0 0 0
91–96 \x5B–\x60 \133–\140 [\]^_` 0 β‰ 0 0 0 β‰ 0 β‰ 0 0 0 0 0 0 0
97–102 \x61–\x66 \141–\146 abcdef 0 β‰ 0 0 0 β‰ 0 0 β‰ 0 β‰ 0 0 β‰ 0 0 β‰ 0
103–122 \x67–\x7A \147–\172 ghijklmnop
qrstuvwxyz 		0 β‰ 0 0 0 β‰ 0 0 β‰ 0 β‰ 0 0 β‰ 0 0 0
123–126 \x7B–\x7E \173–\176 {|}~ 0 β‰ 0 0 0 β‰ 0 β‰ 0 0 0 0 0 0 0
127 \x7F \177 backspace character (DEL) β‰ 0 0 0 0 0 0 0 0 0 0 0 0
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