{{keywords>wiki library source code example reference}}
====== isalnum ======
<code cpp>
    int isalnum(int chr);
</code>
check if a character Alphanumeric

===== cpp Sourcecode Example =====
<code cpp>
#include <iostream> /* including standard library */
#include <string>
#include <cctype>

using namespace std;
int main ()
{
  int i;
  string str="Test -!&%1";
  for (i=0; i <= 11;i++)
    {
     if ( isalnum(str[i]) != 0 )
      {
       cout << "Character " << i << " is alphanumeric" << endl;
      }
    }
  return 0;
}
</code>
==== output ====
    Character 0 is alphanumeric
    Character 1 is alphanumeric
    Character 2 is alphanumeric
    Character 3 is alphanumeric
    Character 9 is alphanumeric