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std::isspace(3)		      C++ Standard Libary	       std::isspace(3)

NAME
       std::isspace - std::isspace

Synopsis
	  Defined in header <cctype>
	  int isspace( int ch );

	  Checks  if the given character is whitespace character as classified
       by the currently
	  installed C locale. In the default locale, the whitespace characters
       are the
	  following:

	    * space (0x20, ' ')
	    * form feed	(0x0c, '\f')
	    * line feed	(0x0a, '\n')
	    * carriage return (0x0d, '\r')
	    * horizontal tab (0x09, '\t')
	    * vertical tab (0x0b, '\v')

	  The behavior is undefined if the value of ch is not representable as
       unsigned	char
	  and is not equal to EOF.

Parameters
	  ch - character to classify

Return value
	  Non-zero value if the	character is a whitespace character, zero oth-
       erwise.

Notes
	  Like all other functions from	<cctype>, the behavior of std::isspace
       is undefined if
	  the argument's value is neither representable	as unsigned  char  nor
       equal to	EOF. To
	  use  these  functions	safely with plain chars	(or signed chars), the
       argument	should
	  first	be converted to	unsigned char:

	bool my_isspace(char ch)
	{
	    return std::isspace(static_cast<unsigned char>(ch));
	}

	  Similarly, they should not be	directly used with standard algorithms
       when the
	  iterator's value type	is char	or signed char.	Instead,  convert  the
       value to	unsigned
	  char first:

	int count_spaces(const std::string& s)
	{
	    return std::count_if(s.begin(), s.end(),
			      //	static_cast<int(*)(int)>(std::isspace)
       // wrong
			      //  [](int   c){	 return	  std::isspace(c);   }
       // wrong
			      //   [](char   c){   return  std::isspace(c);  }
       // wrong
				 [](unsigned char c){ return  std::isspace(c);
       } // correct
				);
	}

See also
	  isspace(std::locale)	checks	if a character is classified as	white-
       space by	a locale
			       (function template)
	  iswspace	       checks if a wide	character is a space character
			       (function)

		 ASCII values		   characters	 iscntrl  isprint  is-
       space  isblank  isgraph	ispunct	 isalnum   isalpha   isupper   islower
       isdigit	isxdigit
	decimal	  hexadecimal	  octal			    iswcntrl  iswprint
       iswspace	iswblank iswgraph iswpunct iswalnum iswalpha iswupper iswlower
       iswdigit	iswxdigit 08	 \x0\x8	  \0\10	   control  codes     0	     0
       0	 0	   0	     0	       0	 0	   0	     0
       0	0
					 (NUL,	  etc.)	     9		   \x9
       \11	    tab	 (\t)	       0     0	       0      0	    0	     0
       0	0	 0	  0	   0	    0
					 whitespaces  1013    \xA\xD	\12\15
       (\n,  \v,  \f,	   0	  0	    0	  0	   0	    0	     0
       0	0	 0	  0	   0
					 \r) 1431   \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  3347    \x21\x2F	\41\57	   !"#$%&'()*+,-./   0
       0      0		0	   0	   0	  0	   0	    0	     0
       0	0 4857	 \x30\x39 \60\71   0123456789	   0	      0	     0
       0	  0	 0	    0	  0	   0	    0	      0	     0
       5864   \x3A\x40 \72\100	:;<=>?@		 0	    0	   0	     0
       0       0      0		0	  0	    0	      0		0 6570
       \x41\x46	\101\106 ABCDEF		 0	   0	 0	  0	     0
       0	  0	  0	  0	 0	   0	     0 7190   \x47\x5A
       \107\132	GHIJKLMNOP	0	  0	 0	   0	      0	     0
       0      0	     0	   0	    0	     0
					 QRSTUVWXYZ  9196    \x5B\x60 \133\140
       [\]^_`	       0	  0	 0	   0	      0	      0	     0
       0	 0	   0	    0	     0 97102  \x61\x66 \141\146	abcdef
       0	 0     0	 0	    0	   0	      0	      0	     0
       0      0		0 103122 \x67\x7A \147\172 ghijklmnop	   0	     0
       0	0	  0	 0	    0	    0	   0	      0	     0
       0
					 qrstuvwxyz  123126  \x7B\x7E \172\176
       {|}~	       0	  0	 0	   0	      0	      0	     0
       0	 0	   0	     0	       0  127	     \x7F	  \177
       backspace	0     0	       0	0	 0	   0	     0
       0	0	 0	  0	   0
					 character (DEL)

http://cppreference.com		  2022.07.31		       std::isspace(3)

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