towctrans() function in C/C++

The towctrans() is a built-in function in C/C++ which applies a transformation to the wide character wc specified by desc. It is defined within the cwctype header file of C/C++.

Syntax:

wint_t towctrans(wint_t wc, wctype_t desc)

Parameter: The function accepts two mandatory parameter which are described below:

• wc – The wide character which needs to be transformed.
• desc – The transformation which is obtained from a call to wctrans().

Return Value: The function returns two values as shown below:

• If wc has the property specified by desc then it returns non zero value.
• If it does not has the property, it returns zero.

Below programs illustrates the above function.

Program 1:

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

int main()
{
    wchar_t str[] = L"Switching Case";
    wcout << L"Before transformation" << endl;
    wcout << str << endl;

    for (int i = 0; i < wcslen(str); i++) {

        // checks if it is lowercase
        if (iswctype(str[i], wctype("lower")))

            // transform character to uppercase
            str[i] = towctrans(str[i], wctrans("toupper"));

        // checks if it is uppercase
        else if (iswctype(str[i], wctype("upper")))

            // transform character to uppercase
            str[i] = towctrans(str[i], wctrans("tolower"));
    }

    wcout << L"After transformation" << endl;

    // prints the transformed string
    wcout << str << endl;
    return 0;
}

Output:

Before transformation
Switching Case
After transformation
sWITCHING cASE

Program 2:

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

int main()
{
    wchar_t str[] = L"gFg iS fUN";
    wcout << L"Before transformation" << endl;
    wcout << str << endl;

    for (int i = 0; i < wcslen(str); i++) {

        // checks if it is lowercase
        if (iswctype(str[i], wctype("lower")))
            // transform character to uppercase
            str[i] = towctrans(str[i], wctrans("toupper"));

        // checks if it is uppercase
        else if (iswctype(str[i], wctype("upper")))

            // transform character to lowercase
            str[i] = towctrans(str[i], wctrans("tolower"));
    }

    wcout << L"After transformation" << endl;

    // prints the transformed string
    wcout << str << endl;
    return 0;
}

Output:

Before transformation
gFg iS fUN
After transformation
GfG Is Fun