wctype() function in C/C++

The wctype() is a built-in function in C/C++ which returns a value of type wctype_t that is used for classifying a wide character. It is defined within the cwctype header file of C++. The following are the possible type wctype_t:

Value of str	Equivalent function
space	iswspace
upper	iswupper
xdigit	iswxdigit
print	iswprint
punct	iswpunct
graph	iswgraph
lower	iswlower
cntrl	iswcntrl
digit	iswdigit
alpha	iswalpha
blank	iswblank
alnum	iswalnum

Syntax:

wctype_t wctype(const char* str)

Parameter: The function accepts a single mandatory parameter str which specifies the desired wctype category. Return Value: The function returns two values as shown below:

• The function returns a wctype_t object that can be used with iswctype() ortowctype() to check a wide character's property.
• If str doesn't provide a category supported by the current C locale, it returns zero.

Below programs illustrates the above function. Program 1: CPP

#include <bits/stdc++.h>
using namespace std;

int main()
{
    wchar_t wc = L'@';

    // checks if the type is digit
    if (iswctype(wc, wctype("digit")))
        wcout << wc << L" is a digit";

    // checks if the type is alpha
    else if (iswctype(wc, wctype("alpha")))
        wcout << wc << L" is an alphabet";

    else
        wcout << wc << L" is neither an"
              << " alphabet nor a digit";

    return 0;
}

Output:

@ is neither an alphabet nor a digit

Program 2: CPP

#include <bits/stdc++.h>
using namespace std;

int main()
{
    wchar_t wc = L'g';

    // checks if the type is digit
    if (iswctype(wc, wctype("digit")))
        wcout << wc << L" is a digit";

    // checks if the type is alpha
    else if (iswctype(wc, wctype("alpha")))
        wcout << wc << L" is an alphabet";

    else
        wcout << wc << L" is neither"
              << " an alphabet nor a digit";

    return 0;
}