iswalnum


iswalnum

Ascertains whether a given wide character is alphanumeric

 #include <wctype.h> int iswalnum ( wint_t wc  ); 

The iswalnum( ) function is the wide-character version of the isalnum( ) character classification function. It tests whether its character argument is alphanumeric; that is, whether the character is either a letter of the alphabet or a digit. If the character is alphanumeric, iswalnum( ) returns a nonzero value (that is, TRue); if not, the function returns 0 (false).

Which characters are considered alphabetic or numeric depends on the current locale setting for the localization category LC_CTYPE, which you can query or change using the setlocale( ) function. In general, iswalnum( ) is true for all characters for which either iswalpha( ) or iswdigit( ) is true.

Example

 wint_t wc, i; int j, dummy; setlocale( LC_CTYPE, "" ); wprintf( L"\nThe current locale for the 'is ...' functions is '%s'.\n",          setlocale( LC_CTYPE, NULL ) ); wprintf( L"These are the alphanumeric wide characters"          " in this locale:\n\n" ); for ( wc = 0, i = 0; wc < 1024; wc++ )   if ( iswalnum( wc ) )     {       if ( i % 25 == 0 )         {           wprintf( L"... more ...\n" );           dummy = getchar( );           // Wait a moment before printing more           wprintf( L"Wide character     Code\n" );           wprintf( L"-----------------------\n" );         }       wprintf(   L"%5lc            %4lu\n", wc, wc );       i++;     } wprintf( L"-----------------------\n" ); return 0; 

Here are samples from the output of this code. Which characters can be displayed correctly on the screen depends on the font used:

 The current locale for the 'is ...' functions is 'de_DE.UTF-8'. These are the alphanumeric wide characters in this locale: Wide character     Code -----------------------      0           48      1           49      2           50 ...               254       ÿ        255               256               257               258               259      

260

261

See Also

iswalpha( ) and iswdigit( ); the corresponding function for byte characters, isalnum( ); iswblank( ), iswcntrl( ), iswgraph( ), iswlower( ), iswprint( ), iswpunct( ), iswspace( ), iswupper( ), iswxdigit( ), setlocale( ); the extensible wide-character classification function, iswctype( )



C(c) In a Nutshell
C in a Nutshell (In a Nutshell (OReilly))
ISBN: 0596006977
EAN: 2147483647
Year: 2006
Pages: 473

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