From cppreference.com
template<classCharT>boolisalnum(CharTch,constlocale&loc);Checks if the given character is classified as an alphanumeric character by the given locale's
facet.
Parameters
ch - character loc - locale Return value
Returns true if the character is classified as alphanumeric, false otherwise.
Possible implementation
template<classCharT>boolisalnum(CharTch,conststd::locale&loc){returnstd::use_facet<std::ctype<CharT>>(loc).is(std::ctype_base::alnum,ch);}Example
Demonstrates the use of isalnum() with different locales (OS-specific).
Run this code
#include<iostream>#include<locale>intmain(){constwchar_tc=L'\u2135';// mathematical symbol alephstd::localeloc1("C");std::cout<<"isalnum('ℵ', C locale) returned "<<std::boolalpha<<std::isalnum(c,loc1)<<'\n';std::localeloc2("en_US.UTF-8");std::cout<<"isalnum('ℵ', Unicode locale) returned "<<std::boolalpha<<std::isalnum(c,loc2)<<'\n';}Possible output:
isalnum('ℵ', C locale) returned false isalnum('ℵ', Unicode locale) returned true See also