std::ctype<CharT>::toupper,std::ctype<CharT>::do_toupper (3) - Linux Manuals

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


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


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.


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.


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.


// 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::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";


  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!'

See also

         invokes do_tolower
tolower (public member function)
         converts a character to uppercase
toupper (function)
         converts a wide character to uppercase
towupper (function)