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 ofch is not representable asunsignedchar and is not equal toEOF.

[edit]Parameters

[edit]Return value

Non-zero value if the character is a whitespace character, zero otherwise.

[edit]Notes

Like all other functions from<cctype>, the behavior ofstd::isspace is undefined if the argument's value is neither representable asunsignedchar nor equal toEOF. To use these functions safely with plainchars (orsignedchars), the argument should first be converted tounsignedchar:

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

Similarly, they should not be directly used with standard algorithms when the iterator's value type ischar orsignedchar. Instead, convert the value tounsignedchar first:

int count_spaces(conststd::string& s){returnstd::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[](unsignedchar c){return std::isspace(c);}// correct);}

[edit]Example

#include <cctype>#include <climits>#include <iomanip>#include <iostream> int main(void){std::cout<<std::hex<<std::setfill('0')<<std::uppercase;for(int ch{}; ch<=UCHAR_MAX;++ch)if(std::isspace(ch))std::cout<<std::setw(2)<< ch<<' ';std::cout<<'\n';}

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[edit]See also

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