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std::iswdigit

From cppreference.com
< cpp‎ | string‎ | wide
 
 
Text processing library
 
Defined in header <cwctype>
int iswdigit( wint_t ch );

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

If the value of ch is neither representable as a wchar_t nor equal to the value of the macro WEOF, the behavior is undefined.

Contents

[edit] Parameters

ch - wide character

[edit] Return value

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

[edit] Notes

std::iswdigit and std::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 <clocale>
#include <cwctype>
#include <iostream>
 
void test(wchar_t a3, wchar_t u3, wchar_t j3)
{
 std::wcout << std::boolalpha
 << "\t '" << a3 << "' '" << u3 << "' '" << j3 << "'\n"
 << "iswdigit: "
 << (bool)std::iswdigit(a3) << " "
 << (bool)std::iswdigit(u3) << " "
 << (bool)std::iswdigit(j3) << '\n'
 << "jdigit: "
 << (bool)std::iswctype (a3, std::wctype ("jdigit")) << ' '
 << (bool)std::iswctype (u3, std::wctype ("jdigit")) << ' '
 << (bool)std::iswctype (j3, std::wctype ("jdigit")) << '\n';
}
 
int main()
{
 wchar_t a3 = L'3'; // the ASCII digit 3
 wchar_t u3 = L'三'; // the CJK numeral 3
 wchar_t j3 = L'3'; // the full-width digit 3
 
 std::setlocale (LC_ALL, "en_US.utf8");
 std::wcout << "In American locale:\n";
 test(a3, u3, j3);
 
 std::wcout << "\nIn Japanese locale:\n";
 std::setlocale (LC_ALL, "ja_JP.utf8");
 test(a3, u3, j3);
}

Possible output: 

In American locale:
 '3' '三' '3'
iswdigit: true false false
jdigit: false false false
 
In Japanese locale:
 '3' '三' '3'
iswdigit: true false false
jdigit: false false true

[edit] See also

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

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