isalnum()

Library:  Localization

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Locale convenience function that determines if a character is alphabetic or numeric

#include <locale>

namespace std {
  template <class charT> 
  bool isalnum(charT c, const locale& loc);
}

The isalnum() function returns true if the character passed as a parameter is either part of the alphabet specified by the locale parameter or a decimal digit. Otherwise the function returns false. The check is made using the ctype facet from the locale parameter.

//
//  isalnum.cpp
//
 
#include <iostream>   // for cout, endl
#include <locale>     // for isalnum


int main ()
{
    std::cout << "Alphanumeric ASCII characters: ";

    // iterate
    for (char c = '\0'; c != '\177'; ++c)
        if (std::isalnum (c, std::cout.getloc ()))
            std::cout << c << ' ';

    std::cout << std::endl;

    return 0;
}


Program Output:

Alphanumeric ASCII characters: 0 1 2 3 4 5 6 7 8 9 A B C D E F G
H I J K L M N O P Q R S T U V W X Y Z a b c d e f g h i j k l m
n o p q r s t u v w x y z 

ctype, locale, isalpha(), iscntrl(), isdigit(), isgraph(), islower(), isprint(), ispunct(), isspace(), isupper(), isxdigit()

ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 22.1.3.1