on Sat Sep 24 2011, Andrew Sutton <asutton.list-AT-gmail.com> wrote:
template< class T, class L, class U >
typename common_type< T const &, L const &, U const & >::type clamp(T const & x, L const & lower, U const & upper) { return x < lower ? lower : upper < x ? upper : x; }
for the use of common_type (assuming it accepts 3 parameters, which I seem to remember it did; if not, just nest); and something like
Can we please not define algorithms this way? It may be possible, but that doesn't mean its a good idea. I don't know how you could possibly prove that the algorithm preserves ordering (<) when the algorithm includes 5 possibly different types.
Thats not strictly true. I do know how you can prove it preserves ordering, but I'm not going to encourage the style.
Define it in terms of a single type and let conversions happen at the call type.
+1. The point is that you probably don't really understand what it means to order different types, and the theorems required to make it semantically well-founded are complicated enough that users of the algorithms won't be able to know whether they're using it properly. -- Dave Abrahams BoostPro Computing http://www.boostpro.com