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std::iswalpha

Defined in header <cwctype> 
int iswalpha( std::wint_t ch );

Checks if the given wide character is an alphabetic character, i.e. either an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), a lowercase letter (abcdefghijklmnopqrstuvwxyz) or any alphabetic character specific to the current locale.

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 alphabetic character, 0 otherwise.

Notes

ISO 30112 specifies which Unicode characters are include in POSIX alpha category.

Example

#include <iostream>
#include <cwctype>
#include <clocale>
 
int main()
{
    wchar_t c = L'\u0b83'; // Tamil sign Visarga ('ஃ')
 
    std::cout << std::hex << std::showbase << std::boolalpha;
    std::cout << "in the default locale, iswalpha(" << (std::wint_t)c << ") = "
              << (bool)std::iswalpha(c) << '\n';
    std::setlocale(LC_ALL, "en_US.utf8");
    std::cout << "in Unicode locale, iswalpha(" << (std::wint_t)c << ") = "
              << (bool)std::iswalpha(c) << '\n';
}

Output:

in the default locale, iswalpha(0xb83) = false
in Unicode locale, iswalpha(0xb83) = true

See also

checks if a character is classified as alphabetic by a locale
(function template)
checks if a character is alphabetic
(function)
C documentation for iswalpha
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.) ≠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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