C++ iswalnum()

The iswalnum() function in C++ checks if the given wide character is an alphanumeric character or not.

The iswalnum() function is defined in <cwctype> header file.

iswalnum() prototype

int iswalnum(wint_t ch);

The iswalnum() function checks if ch is an alphanumeric character or not. The following characters are alphanumeric:

  • Uppercase letters: A to Z
  • Lowercase letters: a to z
  • Digits: 0 to 9

iswalnum() Parameters

  • ch: The wide character to check.

iswalnum() Return value

  • The iswalnum() function returns non zero value if ch is an alphanumeric character.
  • It returns zero if ch is not an alphanumeric character.

Example: How iswalnum() function works?

#include <cwctype>
#include <iostream>
#include <clocale>
using namespace std;

int main()
{
	setlocale(LC_ALL, "en_US.UTF-8");
	
	wchar_t wc1 = L'\u00b6';
	wchar_t wc2 = L'\u00c5';
	wcout << L"In the current locale" << endl;
	
	iswalnum(wc1)?wcout << wc1 << " is alphanumeric ":wcout << wc1 << " is not alphanumeric ";
	wcout << endl;
	iswalnum(wc2)?wcout << wc2 << " is alphanumeric ":wcout << wc2 << " is not alphanumeric ";
	
	return 0;
}

When you run the program, the output will be:

In the current locale
¶ is not alphanumeric
Å is alphanumeric