IS THERE A FUNCTION FOR CONVERTING A STRING TO UPPERCASE

[ayanda83]

OK, Here is the problem, I need to know is there is a string function that can convert the whole string into uppercase instead of the function toupper(char) which does it character by character.

[o1vk4iN6]

If you know it's all characters and no symbols you can simply do char c; c = (c & ~(0x20)) for each character. Which will remove the bit that makes a character lower case, either way you need to go through each character.

[webJose]

toupper(): http://www.cplusplus.com/reference/clibrary/cctype/toupper/

It works in a per-character basis, so one usually applies it with a std::transform().

[mtrenkmann]

STL solution:

std::string str = "hello world";
std::transform(str.begin(), str.end(), str.begin(), std::ptr_fun(::toupper));

Boost solution:
http://www.boost.org/doc/libs/1_48_0/doc/html/string_algo/usage.html#id3115204

[ayanda83]

I've tried using the function toupper() and i think im doing something wrong because instead of it returning uppercase characters, it returns integers. whats causing this?

[Moschops]

whats causing this?

You've instructed your compiler to treat them as integer values. Let's see the code.

[Duthomhas]

This might make the difference:

std::transform( s.begin(), s.end(), s.begin(), std::ptr_fun <int, int> ( std::toupper ) );

I have been informed that, for some reason, ptr_fun<>() has been deprecated in C++11 -- which I am not sure I like because it makes for less-readable code IMHO:

std::transform( s.begin(), s.end(), s.begin(), (int(*)(int))( std::toupper )

Alas.
link: http://www.cplusplus.com/forum/general/56945/

[mtrenkmann]

Right, as of n3242, the last freely available C++ working draft, ptr_fun is now deprecated.
For truly C++11 code you would write:

std::transform(s.begin(), s.end(), s.begin(), std::function<char (char)>(::toupper));
// compiled with 'g++ -std=c++0x test.cpp' under linux 

[morando]

Case insensitive compare:

bool ci_compare(const std::wstring& l, const std::wstring& r)
{
	const std::locale loc("");// system locale
	std::pair< std::wstring::const_iterator, std::wstring::const_iterator > result;
	result = std::mismatch(l.begin(), l.end(), r.begin(), 
	[&loc] (std::wstring::value_type chl, std::wstring::value_type chr)
	{ return std::toupper(chl, loc) == std::toupper(chr, loc); } );
	return l.end() == result.first;
}

[Duthomhas]

@mtrenkmann
Ooh, I like std::function<>!

@morando
I like the idea of lambdas, but I think we now have a valid argument for being more obtuse than C...

[JLBorges]

With C++11, I wouldn't take the trouble of using std::transform() for this.

std::string str = "whatever" ;
for( auto& c :  str ) c = std::toupper(c) ;

[Duthomhas]

Yay!