convert string, wstring to lowercase

[Jeremy Pullicino]

I have once seen a solution to convert a string or wstring to lowercase.

Does anyone have it handy?

Thanks,
Jeremy Pullicino

[Vincent Finn]

On Thu, 15 Jan 2004 14:24:50 +0100, "Jeremy Pullicino"

Post by Jeremy Pullicino
I have once seen a solution to convert a string or wstring to lowercase.

std::transform(myString.begin(), myString.end(), mtString.begin(),
tolower);

[Ken Alverson]

Post by Vincent Finn
On Thu, 15 Jan 2004 14:24:50 +0100, "Jeremy Pullicino"

Post by Jeremy Pullicino
I have once seen a solution to convert a string or wstring to lowercase.

std::transform(myString.begin(), myString.end(), mtString.begin(),
tolower);

Careful, I believe this will compile for wstrings (because tolower takes
ints), but it won't do what you want it to (it'll treat your unicode as
ascii). I don't think there is a C++ standard way to lowercase wchars...on
win32, you can do it with the function CharLower[W], but you'll need to wrap
it to use it in a std::transform, because it represents the epitome of how not
to create an API.

Ken

[Igor Tandetnik]

Post by Ken Alverson
I don't think there is a C++ standard way to lowercase wchars...

ctype<wchar_t>::tolower, std::tolower<wchar_t>(wchar_t, locale)

[Ken Alverson]

Post by Igor Tandetnik

Post by Ken Alverson
I don't think there is a C++ standard way to lowercase wchars...

ctype<wchar_t>::tolower, std::tolower<wchar_t>(wchar_t, locale)

Whoops. Good catch!

Ken

[Sean Kelly]

Post by Igor Tandetnik
ctype<wchar_t>::tolower, std::tolower<wchar_t>(wchar_t, locale)

Here's a reasonable implementation of a conversion object, benefit being
the ctype info is only retrieved once:


template<typename Ty>
struct to_lower :
public std::unary_function<Ty,Ty>
{
public:
to_lower() :
m_ct( std::use_facet<std::ctype<Ty> >( std::locale::classic() ) ) {}
Ty operator()( Ty in ) const { return m_ct.tolower( in ); }
private:
std::ctype<Ty> const& m_ct;
};


Sean