/*FUNCTION	<<iswdigit>>---decimal digit wide-character testINDEX	iswdigitANSI_SYNOPSIS	#include <wctype.h>	int iswdigit(wint_t <[c]>);TRAD_SYNOPSIS	#include <wctype.h>	int iswdigit(<[c]>)	wint_t <[c]>;DESCRIPTION<<iswdigit>> is a function which classifies wide-character values thatare decimal digits.RETURNS<<iswdigit>> returns non-zero if <[c]> is a decimal digit wide-character.PORTABILITY<<iswdigit>> is C99.No supporting OS subroutines are required.*/#include <_ansi.h>#include <wctype.h>int_DEFUN(iswdigit,(c), wint_t c){  return (c >= (wint_t)'0' && c <= (wint_t)'9');}