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# std::ctype::toupper, std::ctype::do_toupper

From cppreference.com
< cpp‎ | locale‎ | ctype

Defined in header `<locale>` |  |
public: CharT toupper( CharT c ) const; | (1) |
public: const CharT* toupper( CharT* beg, const CharT* end ) const; | (2) |
protected: virtual CharT do_toupper( CharT c ) const; | (3) |
protected: virtual const CharT* do_toupper( CharT* beg, const CharT* end ) const; | (4) |

1,2) public member function, calls the protected virtual member function `do_toupper` of the most derived class.
3) Converts the character `c` to upper case if an upper case form is defined by this locale.
4) For every character in the character array `[beg, end)`, for which an upper case form exists, replaces the character with that upper case form.

### [edit] Parameters

c | - | character to convert
beg | - | pointer to the first character in an array of characters to convert
end | - | one past the end pointer for the array of characters to convert

### [edit] Return value

1,3) upper case character or `c` if no upper case form is listed by this locale.
2,4) `end`.

### [edit] Notes

Only 1:1 character mapping can be performed by this function, e.g. the uppercase form of 'ß' is (with some exceptions) the two-character string "SS", which cannot be obtained by `do_toupper`.

### [edit] Example

Run this code

    #include <locale>
    #include <iostream>

    void try_upper(const std::ctype<wchar_t>& f, wchar_t c)
    {
        wchar_t up = f.toupper(c);
        if (up != c) {
            std::wcout << "Upper case form of \'" << c << "' is " << up << '\n';
        } else {
            std::wcout << '\'' << c << "' has no upper case form\n";
        }
    }

    int main()
    {
        std::locale::global(std::locale("en_US.utf8"));
        std::wcout.imbue(std::locale());
        std::wcout << "In US English UTF-8 locale:\n";
        auto& f = std::use_facet<std::ctype<wchar_t>>(std::locale());
        try_upper(f, L's');
        try_upper(f, L'ſ');
        try_upper(f, L'ß');

        std::wstring str = L"Hello, World!";
        std::wcout << "Uppercase form of the string '" << str << "' is ";
        f.toupper(&str[0], &str[0] + str.size());
        std::wcout << "'" << str << "'\n";
    }

Output:

    In US English UTF-8 locale:
    Upper case form of 's' is S
    Upper case form of 'ſ' is S
    'ß' has no upper case form
    Uppercase form of the string 'Hello, World!' is 'HELLO, WORLD!'

### [edit] See also

tolower | invokes `do_tolower` (public member function) [edit]
toupper | converts a character to uppercase (function) [edit]
towupper | converts a wide character to uppercase (function) [edit]

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