Movatterモバイル変換

[0]ホーム
URL:

cppreference.com
Namespaces
Variants
    Actions

      isalpha

      From cppreference.com
      <c‎ |string‎ |byte
       
       
       
       
      Defined in header<ctype.h>
      int isalpha(int ch);

      Checks if the given character is an alphabetic character, i.e. either an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), or a lowercase letter (abcdefghijklmnopqrstuvwxyz).

      In locales other than"C", an alphabetic character is a character for whichisupper() orislower() returnstrue or any other character considered alphabetic by the locale. In any case,iscntrl(),isdigit(),ispunct() andisspace() will returnfalse for this character.

      The behavior is undefined if the value ofch is not representable asunsignedchar and is not equal toEOF.

      Contents

      [edit]Parameters

      ch - character to classify

      [edit]Return value

      Non-zero value if the character is an alphabetic character, zero otherwise.

      [edit]Example

      Demonstrates the use ofisalpha with different locales (OS-specific).

      Run this code
      #include <ctype.h>#include <locale.h>#include <stdio.h> int main(void){unsignedchar c='\xdf';// German letter ß in ISO-8859-1 printf("isalpha('\\xdf') in default C locale returned %d\n",!!isalpha(c)); setlocale(LC_CTYPE,"de_DE.iso88591");printf("isalpha('\\xdf') in ISO-8859-1 locale returned %d\n",!!isalpha(c));}

      Possible output:

      isalpha('\xdf') in default C locale returned 0isalpha('\xdf') in ISO-8859-1 locale returned 1

      [edit]References

      • C23 standard (ISO/IEC 9899:2024):
      • 7.4.1.2 The isalpha function (p: TBD)
      • C17 standard (ISO/IEC 9899:2018):
      • 7.4.1.2 The isalpha function (p: 145)
      • C11 standard (ISO/IEC 9899:2011):
      • 7.4.1.2 The isalpha function (p: 200-201)
      • C99 standard (ISO/IEC 9899:1999):
      • 7.4.1.2 The isalpha function (p: 181-182)
      • C89/C90 standard (ISO/IEC 9899:1990):
      • 4.3.1.2 The isalpha function

      [edit]See also

      checks if a wide character is alphabetic
      (function)[edit]
      ASCII valuescharacters

      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–\10control codes (NUL, etc.)≠000000000000
      9\x9\11tab (\t)≠00≠0≠000000000
      10–13\xA–\xD\12–\15whitespaces (\n,\v,\f,\r)≠00≠0000000000
      14–31\xE–\x1F\16–\37control codes≠000000000000
      32\x20\40space0≠0≠0≠000000000
      33–47\x21–\x2F\41–\57!"#$%&'()*+,-./0≠000≠0≠0000000
      48–57\x30–\x39\60–\7101234567890≠000≠00≠0000≠0≠0
      58–64\x3A–\x40\72–\100:;<=>?@0≠000≠0≠0000000
      65–70\x41–\x46\101–\106ABCDEF0≠000≠00≠0≠0≠000≠0
      71–90\x47–\x5A\107–\132GHIJKLMNOP
      QRSTUVWXYZ      		0≠000≠00≠0≠0≠0000
      91–96\x5B–\x60\133–\140[\]^_`0≠000≠0≠0000000
      97–102\x61–\x66\141–\146abcdef0≠000≠00≠0≠00≠00≠0
      103–122\x67–\x7A\147–\172ghijklmnop
      qrstuvwxyz      		0≠000≠00≠0≠00≠000
      123–126\x7B–\x7E\173–\176{|}~0≠000≠0≠0000000
      127\x7F\177backspace character (DEL)≠000000000000
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=c/string/byte/isalpha&oldid=181275"
      [8]ページ先頭
      ©2009-2025 Movatter.jp