C++ Locale Library - isalnum

Description

It checks if character is alphanumeric.

Declaration

Following is the declaration for std::isalnum.

C++98

int isalnum ( int c );

C++11

int isalnum ( int c );

Parameters

c − Character to be checked, casted to an int, or EOF.

Return Value

It returns a value different from zero.

Exceptions

No-throw guarantee − this function never throws exceptions.

Example

In below example for std::isxdigit.

#include <stdio.h>
#include <ctype.h>
int main () {
   int i;
   char str[]="sairamkrishna1234566789.";
   i=0;
   while (isalnum(str[i])) i++;
   printf ("The first %d characters are alphanumeric.\n",i);
   return 0;
}

The sample output should be like this −

The first 23 characters are alphanumeric.