C++ <cwctype> - iswalnum() Function

The C++ <cwctype> iswalnum() function is used to check if the given wide character is an alphanumeric letter. An alphanumeric letter is either a decimal digit or an uppercase or lowercase letter. In the default "C" locale, an alphanumeric letter is a letter for which either iswdigit() or iswupper() or iswlower() function returns true. Other locales may consider a different selection of wide characters as alphanumeric letters.

Syntax

int iswalnum ( wint_t ch );               

Parameters

Return Value

Returns non-zero value (i.e, true) if ch is an alphanumeric letter, else returns zero (i.e, false).

Example:

The example below shows the usage of iswalnum() function.

#include <iostream>
#include <cwchar>
#include <cwctype>
using namespace std;
 
int main (){
  wchar_t str[50] = L"98Hi@@";

  //counting the numbers of 
  //alphanumeric letters in str
  int i = 0, count = 0;
  while(str[i]) {
    if(iswalnum(str[i]))
      count++;
    i++;
  }

  //displaying the output
  wcout<<str<<" contains "<<count<<
       " alphanumeric letters.";  
  return 0;
}

The output of the above code will be:

98Hi@@ contains 4 alphanumeric letters.