std::iswdigit
From cppreference.com
| Defined in header <cwctype>
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| int iswdigit( wint_t ch ); |
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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.
Parameters
| ch | - | wide character |
Return value
Non-zero value if the wide character is a numeric character, zero otherwise.
Notes
std::iswdigit and std::iswxdigit are the only standard wide character classification functions that are not affected by the currently installed C locale.
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 trueSee also
| checks if a character is classified as a digit by a locale (function template) | |
| checks if a character is a digit (function) | |
| C documentation for iswdigit
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| ASCII values | characters |
isdigit |
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| decimal | hexadecimal | octal | |||||||||||||
| 0–8 | \x0–\x8
|
\0–\10
|
control codes (NUL, etc.)
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 9 | \x9
|
\11
|
tab (\t)
|
≠0
|
0
|
≠0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 10–13 | \xA–\xD
|
\12–\15
|
whitespaces (\n, \v, \f, \r)
|
≠0
|
0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 14–31 | \xE–\x1F
|
\16–\37
|
control codes | ≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 32 | \x20
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\40
|
space | 0
|
≠0
|
≠0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 33–47 | \x21–\x2F
|
\41–\57
|
!"#$%&'()*+,-./
|
0
|
≠0
|
0
|
0
|
≠0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 48–57 | \x30–\x39
|
\60–\71
|
0123456789
|
0
|
≠0
|
0
|
0
|
≠0
|
0
|
≠0
|
0
|
0
|
0
|
≠0
|
≠0
|
| 58–64 | \x3A–\x40
|
\72–\100
|
:;<=>?@
|
0
|
≠0
|
0
|
0
|
≠0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 65–70 | \x41–\x46
|
\101–\106
|
ABCDEF
|
0
|
≠0
|
0
|
0
|
≠0
|
0
|
≠0
|
≠0
|
≠0
|
0
|
0
|
≠0
|
| 71–90 | \x47–\x5A
|
\107–\132
|
GHIJKLMNOPQRSTUVWXYZ
|
0
|
≠0
|
0
|
0
|
≠0
|
0
|
≠0
|
≠0
|
≠0
|
0
|
0
|
0
|
| 91–96 | \x5B–\x60
|
\133–\140
|
[\]^_`
|
0
|
≠0
|
0
|
0
|
≠0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 97–102 | \x61–\x66
|
\141–\146
|
abcdef
|
0
|
≠0
|
0
|
0
|
≠0
|
0
|
≠0
|
≠0
|
0
|
≠0
|
0
|
≠0
|
| 103–122 | \x67–\x7A
|
\147–\172
|
ghijklmnopqrstuvwxyz
|
0
|
≠0
|
0
|
0
|
≠0
|
0
|
≠0
|
≠0
|
0
|
≠0
|
0
|
0
|
| 123–126 | \x7B–\x7E
|
\172–\176
|
{|}~
|
0
|
≠0
|
0
|
0
|
≠0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
| 127 | \x7F
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\177
|
backspace character (DEL)
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|