The iswalnum() is a built-in function in C++ STL which checks if the given wide character is an alphanumeric character or not. It is defined within the cwctype header file of C++.
The following characters are alphanumeric:
- Uppercase letters: A to Z
- Lowercase letters: a to z
- Digits: 0 to 9
Parameter: The function accepts a single mandatory parameter ch which specifies the wide character which we have to check that if it is alphanumeric or not.
Return Value: The function returns two values as shown below.
- If the ch is an alphanumeric character, then a non-zero value is returned.
- If it is not then 0 is returned.
Below programs illustrates the above function.
? is not alphanumeric g is alphanumeric
3 is alphanumeric & is not alphanumeric
- Function Overloading vs Function Overriding in C++
- What happens when a virtual function is called inside a non-virtual function in C++
- Difference between Virtual function and Pure virtual function in C++
- exp() function C++
- log() function in C++
- div() function in C++
- fma() function in C++
- towlower() function in C/C++
- iswxdigit() function in C/C++
- iswctype() function in C/C++
- wctype() function in C/C++
- strtoimax() function in C++
- strtoumax() function in C++
- strrchr() function in C/C++
- strcspn() function in C/C++
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.