Std::ctype::toupper,std::ctype::do_toupper (3) Linux Manual Page

std::ctype<CharT>::toupper,std::ctype<CharT>::do_toupper – std::ctype<CharT>::toupper,std::ctype<CharT>::do_toupper

Synopsis

Defined in header<locale>

    public : (1)

                 CharT toupper(CharT c) const;

public:
(2)

    const CharT *toupper(CharT *beg, const CharT *end) const;

protected:
(3)

    virtual CharT do_toupper(CharT c) const;

protected:
(4)

    virtual const CharT *do_toupper(CharT *beg, const CharT *end) const;

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.

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

Return value

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

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.

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!’

std::ctype::toupper,std::ctype::do_toupper (3) Linux Manual Page