Commas

[Technocrat]

Anyone got some code to put commas into a string of numbers?

ie "1234" = "1,230" "1234567890" = "1,234,567,890"

[CornedBee]

C++

template <typename _C, typename _Traits, typename _Alloc>
inline std::basic_string<_C, _Traits, _Alloc> & add_commas(
		   const std::basic_string<_C, _Traits, _Alloc> & in,
		   std::basic_string<_C, _Traits, _Alloc> & out)
{
	out.reserve(in.length()+(in.length()/3));
	std::basic_string<_C, _Traits, _Alloc> temp = in;
	std::reverse(temp.begin(), temp.end());
	for(std::basic_string<_C, _Traits, _Alloc>::const_iterator i=temp.begin();
		i!=temp.end(); ++i)
	{
		std::iterator_traits<std::basic_string<_C, _Traits, _Alloc>::const_iterator>
			::difference_type diff = i-temp.begin();
		if(diff>0 && diff%3==0)
			out.push_back(std::use_facet<std::ctype<_C> >(std::locale()).widen(','));
		out.push_back(*i);
	}
	std::reverse(out.begin(), out.end());
	return out;
}

100% standards compliant, but not really locale sensitive (some locales want a . inserted instead of a ,)

[CornedBee]

Locale definition returns a NUL-char for the thousands seperator for me...

You'll have to do with this one.

[Technocrat]

Ok thanks this at least gives me something to work with.

[Technocrat]

Hmm I keep getting

error C2039: 'reverse' : is not a member of 'std'

Any ideas?

[CornedBee]

Sorry, you need these headers:
<string>
<locale>
<algorithm>

[Technocrat]

Ok thanks up and running now

[CornedBee]

np, if you want anything else (like an explanation ) just ask.

[Technocrat]

Actually I am only familure with the basics of templates, yet this seem pretty self exlanitory if you just think about it.