From cppreference.com
intisblank(intch);(since C++11)Checks if the given character is a blank character as classified by the currently installed C locale. Blank characters are whitespace characters used to separate words within a sentence. In the default C locale, only space (0x20) and horizontal tab (0x09) are classified as blank characters.
The behavior is undefined if the value of ch is not representable as unsignedchar and is not equal to
.
Parameters
ch - character to classify Return value
Non-zero value if the character is a blank character, zero otherwise.
Notes
Like all other functions from
, the behavior of std::isblank is undefined if the argument's value is neither representable as unsignedchar nor equal to EOF. To use these functions safely with plain chars (or signedchars), the argument should first be converted to unsignedchar:
boolmy_isblank(charch){returnstd::isblank(static_cast<unsignedchar>(ch));}Similarly, they should not be directly used with standard algorithms when the iterator's value type is char or signedchar. Instead, convert the value to unsignedchar first:
intcount_blanks(conststd::string&s){returnstd::count_if(s.begin(),s.end(),// static_cast<int(*)(int)>(std::isblank) // wrong// [](int c){ return std::isblank(c); } // wrong// [](char c){ return std::isblank(c); } // wrong[](unsignedcharc){returnstd::isblank(c);}// correct);}See also
ASCII values characters
decimal hexadecimal octal 0–8 \x0–\x8\0–\10control codes (NUL, etc.) ≠0000000000009 \x9\11tab (\t) ≠00≠0≠00000000010–13 \xA–\xD\12–\15whitespaces (\n, \v, \f, \r) ≠00≠000000000014–31 \xE–\x1F\16–\37control codes ≠00000000000032 \x20\40space 0≠0≠0≠00000000033–47 \x21–\x2F\41–\57!"#$%&'()*+,-./0≠000≠0≠000000048–57 \x30–\x39\60–\7101234567890≠000≠00≠0000≠0≠058–64 \x3A–\x40\72–\100:;<=>?@0≠000≠0≠000000065–70 \x41–\x46\101–\106ABCDEF0≠000≠00≠0≠0≠000≠071–90 \x47–\x5A\107–\132GHIJKLMNOP
QRSTUVWXYZ0≠000≠00≠0≠0≠000091–96 \x5B–\x60\133–\140[\]^_`0≠000≠0≠000000097–102 \x61–\x66\141–\146abcdef0≠000≠00≠0≠00≠00≠0103–122 \x67–\x7A\147–\172ghijklmnop
qrstuvwxyz0≠000≠00≠0≠00≠000123–126 \x7B–\x7E\172–\176{|}~0≠000≠0≠0000000127 \x7F\177backspace character (DEL) ≠000000000000