std::iswdigit
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.
Parameters
ch | - | wide character |
Return value
Non-zero value if the wide character is an 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.
#include <iostream> #include <cwctype> #include <clocale> void test(wchar_t a3, wchar_t u3, wchar_t j3) { std::wcout << std::boolalpha << " '" << 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 fullwidth 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); }
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
See 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 |
ASCII values | characters |
|
|||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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 |
\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 |
GHIJKLMNOP QRSTUVWXYZ |
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 |
ghijklmnop qrstuvwxyz |
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 |
\177 |
backspace character (DEL ) |
≠0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
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